What do you think?
Rate this book
Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past
Goodreads Choice Award
Nominee for Best Science & Technology (2018)Massive technological innovations now allow scientists to extract and analyze ancient DNA as never before, and it has become clear--in part from David Reich's own contributions to the field--that genomics is as important a means of understanding the human past as archeology, linguistics, and the written word. Now, in The New Science of the Human Past, Reich describes just how the human genome provides not only all the information that a fertilized human egg needs to develop but also contains within it the history of our species. He delineates how the Genomic Revolution and ancient DNA are transforming our understanding of our own lineage as modern humans; how genomics deconstructs the idea that there are no biologically meaningful differences among human populations (though without adherence to pernicious racist hierarchies); and how DNA studies reveal the deep history of human inequality--among different populations, between the sexes, and among individuals within a population.
335 pages, Hardcover
First published March 27, 2018
About the author
David Reich
1 book60 followersDavid Emil Reich is an American geneticist known for his research into the population genetics of ancient humans, including their migrations and the mixing of populations, discovered by analysis of genome-wide patterns of mutations. He is a professor in the department of genetics at the Harvard Medical School, and an associate of the Broad Institute. Reich was highlighted as one of Nature's 10 for his contributions to science in 2015. He received the Dan David Prize in 2017, the NAS Award in Molecular Biology, the Wiley Prize, and the Darwin–Wallace Medal in 2019. In 2021 he was awarded the Massry Prize.
Reich received a BA in physics from Harvard University and a Ph.D. in zoology from St. Catherine's College at the University of Oxford. He joined Harvard Medical School in 2003. Reich is currently a geneticist and professor in the department of genetics at Harvard Medical School, and an associate of the Broad Institute, whose research studies compare the modern human genome with those of chimpanzees, Neanderthals, and Denisovans.
Reich's genetics research focuses primarily on finding complex genetic patterns that cause susceptibility to common diseases among large populations, rather than looking for specific genetic markers associated with relatively rare illnesses.
Source: https://en.wikipedia.org/wiki/David_R...
Reich received a BA in physics from Harvard University and a Ph.D. in zoology from St. Catherine's College at the University of Oxford. He joined Harvard Medical School in 2003. Reich is currently a geneticist and professor in the department of genetics at Harvard Medical School, and an associate of the Broad Institute, whose research studies compare the modern human genome with those of chimpanzees, Neanderthals, and Denisovans.
Reich's genetics research focuses primarily on finding complex genetic patterns that cause susceptibility to common diseases among large populations, rather than looking for specific genetic markers associated with relatively rare illnesses.
Source: https://en.wikipedia.org/wiki/David_R...
Ratings & Reviews
Friends & Following
Create a free account to discover what your friends think of this book!
Community Reviews
Displaying 1 - 30 of 768 reviews
September 26, 2020
A book that catalogues the movement and migration of human populations and the current work being done in sequencing and analyzing ancient DNA. Someone recommended this to me and I really enjoyed it. I think it was accessible but also rigorous. It mostly was an overview of the research literature in the domain which I really liked.
I kind of felt ambivalent about the author's qualifications on genetic research and race however, even though I think he did a fair job explaining his position and his position is a reasonable one. I think most of it just has to do with my own skepticism about cognitive/behavioral ties being made to biology. Even though Reich himself acknowledges that they way genes work to influence cognition and behavior may be indirect or counterintuitive to us.
I also think it was weird of him to talk about the genetic link to educational attainment being an explanation rooted in waiting to have kids but then not explaining how the genes that influence both go about causing people to delay having kids. Just because the genes that predict educational attainment more strongly predict people delaying having children doesn't mean the genes are influencing either directly. It mostly felt weird because later on he talks about the need to follow populations overtime because the increase in genetic variations associated with educational attainment being lower in populations over time as those people have less children because of the previously mentioned link. I think it's understandable for someone who comes out explicitly to say they're of the community that follows in the traditions of the Enlightenment (or something to that effect) to be concerned about educational attainment but it seems to me to be a narrow view of what is worthwhile and desirable in human beings to have these concerns with intelligence/education always brought up.
Really good book overall though, would definitely recommend to others interested in the history of human evolution and migration.
I kind of felt ambivalent about the author's qualifications on genetic research and race however, even though I think he did a fair job explaining his position and his position is a reasonable one. I think most of it just has to do with my own skepticism about cognitive/behavioral ties being made to biology. Even though Reich himself acknowledges that they way genes work to influence cognition and behavior may be indirect or counterintuitive to us.
I also think it was weird of him to talk about the genetic link to educational attainment being an explanation rooted in waiting to have kids but then not explaining how the genes that influence both go about causing people to delay having kids. Just because the genes that predict educational attainment more strongly predict people delaying having children doesn't mean the genes are influencing either directly. It mostly felt weird because later on he talks about the need to follow populations overtime because the increase in genetic variations associated with educational attainment being lower in populations over time as those people have less children because of the previously mentioned link. I think it's understandable for someone who comes out explicitly to say they're of the community that follows in the traditions of the Enlightenment (or something to that effect) to be concerned about educational attainment but it seems to me to be a narrow view of what is worthwhile and desirable in human beings to have these concerns with intelligence/education always brought up.
Really good book overall though, would definitely recommend to others interested in the history of human evolution and migration.
June 24, 2018
We geneticists may be the barbarians coming late to the study of the human past, but it is always a bad idea to ignore barbarians. We have access to a type of data that no one has had before, and we are wielding these data to address previously unapproachable questions about who ancient peoples were.. This book has many very, very good qualities. It is, without doubt, the best modern summary of ancient genome research and how it is transforming our understanding of the past available. However, it also carries some very deep, and dangerous, flaws. Reich is so keen to move us forward with new techniques that he tramples past cultural, sociological and anthropological scholarship that helps us to understand how we create narratives and guard against bias. In doing so, his book reinforces destructive ideas about race; human cognition and psychology and class and power. Perhaps ironically, in seeking to free us from antiquated scholarship, Reich plays straight back into dominant narratives that have explained - and justified - racial inequality for centuries.
In many ways these are small flaws, affecting a few chapters at the end. But Reich has created a narrative around this in which he is a hero taking on the idiocy of political correctness, which makes it impossible not to treat this discussion as the center of the book. And as Reich says above, these newcomers to the field of human origins wield enormous influence, which brings with it responsibility for rounded scholarship.
It has taken me a month to write this damn review (long time to have a tab open!) in part because Reich sets us such a trap for the critic: he consistently argues that those critiquing his view of race are motivated by trying to shut the discussion down. People like me are anti-evidence, and unless you are going to argue with him over the sequencing techniques, then the criticism is irrelevant. As it happens, I agree strongly, as do very many who think he is wrong, with the need to have evidence-based discussion about race, gender, intellect, cognition and human origins. Especially given the rise of overt racism, and the flock of racist men to blogs and discussion forums around genetic prehistory. So it has been important to me to ensure that it is clear that my objections are not to having a conversation, they are to his conclusions, and the way he has framed the debate, and most of all, what he overlooks.
Now, Reich argues that he is countering racism: his book strips back the stupid claim that 'races' have existed for any significant fraction of human existence, and gives huge weight - as does all modern genetic work - to understanding that our ancestors mingled, migrated and procreated much more expansively than we had previously assumed. Our modern 'populations' have existed for not much more than 5000 years in most cases. (This itself shows what we mean - many populations actually have been relatively distinct for longer than that, the San, Australia's Aboriginal groups, Native Americans - but they don't correspond to our race ideas, which lump all Africans together, all Oceanic groups together etc - really, it is the inhabitants of Eurasia who have mingled incessantly, creating the populations who tend to hold social, economic and political power in our current world) Multiculturalism has been a consistent feature of human societies, and yes, conflict is as much a part of that condition as harmony: this is part of who we are, in all our glorious complexity. But the fact that Reich doesn't think he is making racist assumptions doesn't change two big errors: his argument that cognitive differences could exist between "large population groups" (i.e.: races) and his infuriating and frankly petulant dismissal of First Nations concerns around genetic research.
On the first: to start, Reich is not in the majority in thinking that large populations are the most effective way to look at genetic difference - he himself outlines his differences with Svante Paabo in the book, although he talks down the support that remains for Paabo's view that clines is a more enlightening slice. He admirably starts by pointing out that race, as we think we understand, has been largely debunked. He attempts to distinguish himself from the rubbish spouted by journalist Nicholas Wade, and the prejudice of James Watson. But as the book progresses, he focuses increasingly on the possibility of differences which have evolved over the last 5000 years, providing markers between populations - despite the fact he presents no evidence for this. In the end, he seems to be warning that they might be right about some things, attacking his colleagues for using truisms like, there is more genetic variation within population groups than between them (this is, by the way, simply true) instead, presumably, of focusing on those differences which can be found. The fact that there is plenty of scholarship on those differences, such as skin colour, height and susceptibility to disease, doesn't count of course, because really what Reich is getting at is cognitive, personality and the "real" question of intelligence. Who is, after all, the most human? the fact we have little idea in any form of scholarship of what that actually means doesn't slow him down at all. And honestly, it should.
On the IQ: look, there are many great articles on this already on the Interwebz. Start with Kevin Mitchell in the Guardian . The issue here isn't that genetics doesn't predict the possibility of natural selection causing complex differences between populations (the only argument that Reich addresses in the book, and one which he says comes from political correctness, adding insult to disagreement); the issue is that the main narrative of modern society is that these differences do exist, when there is no untainted evidence for it. Mitchell in this link accepts the IQ test as a measure of intelligence - but many, many scientists do not. We have much evidence, in fact, that economic inequality and stereotype threat: much of this research is centered on gender difference in maths . This is why the one main significant study into IQ and genetics - which Reich makes much of - focused on a very uniform genetic population in a country with tiny economic and social inequality, and even then the implications of its results have been widely challenged.
Reich's own research on earlier periods challenges the simple search genetics has for the unlocking nature of consciousness and humanity. He points out that despite large resources, there simply doesn't seem to be evidence that genetic adaptation closely precedes leaps in human development. This is not a surprise to evolutionary biologists, who have known for some time that our capacity to learn and create social structures which then shape our individual cognitive development is our strongest adaptation; that our closest primate relatives have genetic capacity for language and tool use, as well as often superior memory and recall. But the key lesson here: that we have an extreme ability to socially shape our children and hence create ourselves should also result in an understanding that we ourselves, us scientists, are also created and shaped by the societies that created us, is one Reich usually doesn't appreciate the impact of.
In one rather infuriating section he comments that we should take the same approach to race as to gender, throwing out:
Most people accept that the biological differences between males and females are profound, and that they contribute to average differences in size and physical strength as well as in temperament and behavior, even if there are questions about the extent to which particular differences are also influenced by social expectations and upbringing (for example, many of the jobs in industry and the professions that women fill in great numbers today had few women in them a century ago). Today we aspire both to recognize that biological differences exist and to accord everyone the same freedoms and opportunities regardless of them. It is clear from the abiding average inequities that persist between women and men that fulfilling these aspirations is a challenge, and yet it is important to accommodate and even embrace the real differences that exist, while at the same time struggling to get to a better place.This view, that gender inequality is just a bit of thorny issue society is working through, that most people accept that gendered differences in 'temperament' are 'profound' bears little resemblance to any serious scholarship on either gender, or neuroscience (which consistently finds less and less gendered differences), or for that matter the goddamn zeitgeist at the moment, and summarises Reich's dismissiveness.
Reich at times shows flashes of insight into how social and biological factors interact: for example noting that genetic predictors in (again, uniform and highly equal society) educational rates may relate to differences in fertility, not cognition, or his wonderful aside that West Africans might not be faster, but just more genetically diverse than others, but when it hasn't been forcefully brought to his attention by a sociologist he met at a dinner party, he seems unaware that what he regards as common knowledge comes from a worldview based on relationships of power and social roles. In this context, his blithe assumption that we can find cognitive differences between populations - despite the complete lack of agreement into how to measure or understand cognition; and an awareness that our "common sense" assumptions are largely shaped by our social environment - is an infuriating result of isolating hard science from the social sciences and humanities.
Nowhere is this lack of awareness that he has a worldview more evident than in his frustrated complaints about the role of First Nations peoples - particularly in the Americas - in refusing participation in genetic testing. Reich's bewilderment as to why this is even an issue is clear:
Scientists interested in studying genetic variation in Native American populations feel frustrated with this situation. I understand something of the devastation that the coming of Europeans and Africans to the Americas wrought on Native American populations, and its effects are also evident everywhere in the data I and my colleagues analyze. But I am not aware of any cases in which research in molecular biology including genetics—a field that has arisen almost entirely since the end of the Second World War—has caused major harm to historically persecuted groups.and leads on to hints of wanting to disregard agreements with tribal councils not to proselytise around this research:
I wonder if the distrust that has emerged among some Native Americans might be, in the balance, doing Native Americans substantial harm. I wonder whether as a geneticist I have a responsibility to do more than just respect the wishes of those who do not wish to participate in genetic research, but instead should make a respectful but strong case for the value of such research.
Reich's claim that his research field has not done harm is a little naive. For starters, it involves his version of harm, which excludes the exploitation of genetic material for the primary gain of other groups. It assumes that his post-Enlightenment worldview - in which the search for information is noble, and never dangerous, and in which experimentation is more worthy than spiritual contemplation, is more worthy than differing worldviews which view knowledge without protection, context and responsibility as dangerous. It also ignores the attempts to patent genomic material in the 1990s, and the thirst for profit that US biomedicine is embroiled in, rarely to the benefit of participants. He lauds the work of researchers working with Aboriginal groups in Australia, without realising apparently that this work rests upon recognising that work with genetic material of Aboriginal groups must meet needs the community has identified. That is, it is about listening, respecting and offering resources: none of which is evident in Reich's approach to any of this.
So, the good bits? Reich loves the pursuit of knowledge and it shows. And while he struggles so much with not recognising he has biases, he is refreshingly free from attaching his ego to particularly theories. He cheerfully admits where genetic research has proven his assumptions wrong, and this makes most of the book a page-turner, able to draw a reader in to rapidly shifting worlds of difference.
Reich tackles a range of topics here: including the sensitive issue that the genetic evidence indicates we have more female ancestors than male. This process results from bottlenecks, or times where men fathered children on a wide range of women. While Reich clearly fears this will upset modern scholars, it is hardly a surprise to anthropologists well aware that polygynous child rearing is more common than polyandry, and that war and conflict are largely driven male invading forces. His research into the Indian caste system is fascinating, indicating the long-term effectiveness of social separation within an existing community, and providing really interesting takes on the interaction between social structures and genetic ones. The Brahmin caste, he argues, is far from purely different genetic stock, but bears markers of centuries of incestuous procreation and social isolation. I wanted far more on the Southern Route theory, and the role of Austronesian analysis - particularly given a month before the book came out, cave art was dated to 60,000 years in Northern Australia, which, if accurate, comes down solidly in favour of an early Southern route expansion (and Denosovan contact after arrival on the continent - or errors in genetic dating). Reich is well aware that this book is written at a moment in time, and it takes a certain courage to do that, as no doubt many of his current theories will be debunked in coming years. In being that brave, he's given the layperson a fabulous chance to explore a field in flux. It is just such a shame that he chose to mar this with an unsubstantiated argument about possible things people may find into the future, in a way which feeds into racism and sexism.
September 16, 2018
This was the book that I wanted the last book I read on the topic to be. Concentrates on the science, lucidly written, although probably best not read when one is too fatigued or sleepy. Its explanations seem as simple as possible but no simpler, which I appreciate. This is a round-up of the most recent (as of about the end of 2017) science of ancient DNA by one of the scientists working on the subject. It's such a fast-moving field right now (faster than print publishing, to be sure) even a year will make a difference, and as a sort of science camp-follower, I look forward to trying to keep up.
I found the work reported on India and Asia to be especially interesting, as it was new to me. (I'd already read Paabo's book on the Neanderthal work, also highly recommended. https://www.goodreads.com/book/show/1... )
Highly recommended, although read it soon, rather like eating your ice cream before it melts.
Ta, L.
December 27, 2020
This book offers readers a description about the human past that has been made possible by recent technological advances in genome research. By comparing whole genomes' worth of DNA from ancient humans of various degrees of antiquity together with the data analysis power of modern computers, a picture of ancient human history has emerged that is filled with multiple migrations by varied branches of the human ancestral family.
The picture that is emerging consists of so many past migrations and mixtures of past populations that it's difficult to know how to give a sense of its complexity in this review. This is compounded by the author's statement that there's an avalanche of new genome data pouring into the field faster than it can be assimilated. The author predicts that the complexity of past human history will become increasingly developed in detail and complexity. The following items highlighted by this review are simply those portions that impressed me as being particularly interesting.
Variation in Human Forms
The variation in human forms varied much more widely 50,000 years ago than it does today. There were at that time alive on earth four major forms of humans. In addition to modern humans there were Neanderthal, Denisovan and Homo-floresiensis (a.k.a Hobbits). The Homo-floresiensis were isolated on the Island of Flores, Indonesia and may have been descendants of Homo-erectus and did not mix with modern humans. However, there was intermixing of Neanderthals and Denisovans with modern humans as late as 50,000± years ago. Almost all non-Sub-Saharan Africans alive today carry traces of this ancestry in their DNA.
DNA Consequences of American Slavery
The contribution of European American men to the average genetic makeup of present-day African Americans is about four times higher than that of European American women (38 percent versus 10 percent). This difference is determined by comparing the differences between Y-chromosone and mitochondrial DNA. This "sex bias" in some human ancestries is evidence of an imbalance in social power between human classes during past history. A similar difference is found in south Asian DNA which is indicative of a past migration or invasion from the Eurasian Steppes. It's interesting how past human sexual behavior, sometimes many years in the past, can be determined by this sort of analysis.
Native Americans Closer to Europeans than Asians
Native Americans are more closely related to Europeans than to East Asians. How can this be if the ancestral native Americans came to North America via the Bering Strait crossing which is in northeast Asia? The answer lies in the past existence of a "ghost population" of "ancient north Eurasians" that contributed to the genome of both northern Europeans and Native Americans, but not present-day Han Chinese.
Ghost Populations
The term "ghost population" is used to describe a population that can be inferred to have existed in the past using statistical reconstruction but that no longer exists in unmixed form. And indeed the bones found in a south-central Siberian grave dating from around 24,000 years ago match the predicted genome of "ancient north Eurasians." The following graphic illustrates the "four population ancestral analysis" that illustrates how the existence of "ancient north Eurasians" was determined.
Sardinians Are Remnant of Early Europeans
It's interesting to note from the above illustration that today's Sardinians are the closest relatives to ancestral Europeans because the mixing with north Eurasians didn't reach them.
Neanderthal Markers in European and Asian DNA
Also of interest from the above illustration is the fact that modern human/Neanderthal mixing occurred with the "ancestral non-Africans" but not with the "predicted ghost population" of ancient north Eurasia. Consequently, present day Han Chinese have a higher percentage of Neanderthal markers in their DNA than present day northern Europeans (4% vs. 2%). This is counter intuitive since the mixing between modern humans and Neanderthal occurred in Europe and the Middle East.
Controversies
The book contains a chapter which discusses some of the controversies caused by the recent advances in genome research. One subject discussed is the refusal of some Native American tribes to allow bones of their ancestors be analyzed. This has developed from a long history of scientists who have shown disrespect to this ethnic group. The author sees this as an unfortunate situation which he hopes can be resolved with time and improved trust between the two sides.
Problems with Racists
Another issue discussed is the problem with those who object to any analysis of differences between human groups because it gives fuel to racists. The author believes that enforcement of artificial political correctness on genome research would allow those of a paranoid disposition to claim that the scientfic community is hiding the "truth." He says it is best to have an open an transparent discussion of genome differences between racial groups.
NYT Article of Interest
The following is a link (not from the book) to an article about an archeological excavation of a grave of a human who was a mixture of Neanderthal and Denisovan, but not modern human.
https://www.nytimes.com/2018/08/22/sc...
Excerpt from Another Book
The following is not from this book. It's a link to an excerpt from Evolving Ourselves by Juan Enriquez and Steve Gullans. I found of particular interest the quote, "There are almost no examples of Neanderthal cavities. Paleolithic and Mesolithic human skulls are almost devoid of cavities." https://t.co/HfAjYUwDoh
The picture that is emerging consists of so many past migrations and mixtures of past populations that it's difficult to know how to give a sense of its complexity in this review. This is compounded by the author's statement that there's an avalanche of new genome data pouring into the field faster than it can be assimilated. The author predicts that the complexity of past human history will become increasingly developed in detail and complexity. The following items highlighted by this review are simply those portions that impressed me as being particularly interesting.
Variation in Human Forms
The variation in human forms varied much more widely 50,000 years ago than it does today. There were at that time alive on earth four major forms of humans. In addition to modern humans there were Neanderthal, Denisovan and Homo-floresiensis (a.k.a Hobbits). The Homo-floresiensis were isolated on the Island of Flores, Indonesia and may have been descendants of Homo-erectus and did not mix with modern humans. However, there was intermixing of Neanderthals and Denisovans with modern humans as late as 50,000± years ago. Almost all non-Sub-Saharan Africans alive today carry traces of this ancestry in their DNA.
DNA Consequences of American Slavery
The contribution of European American men to the average genetic makeup of present-day African Americans is about four times higher than that of European American women (38 percent versus 10 percent). This difference is determined by comparing the differences between Y-chromosone and mitochondrial DNA. This "sex bias" in some human ancestries is evidence of an imbalance in social power between human classes during past history. A similar difference is found in south Asian DNA which is indicative of a past migration or invasion from the Eurasian Steppes. It's interesting how past human sexual behavior, sometimes many years in the past, can be determined by this sort of analysis.
Native Americans Closer to Europeans than Asians
Native Americans are more closely related to Europeans than to East Asians. How can this be if the ancestral native Americans came to North America via the Bering Strait crossing which is in northeast Asia? The answer lies in the past existence of a "ghost population" of "ancient north Eurasians" that contributed to the genome of both northern Europeans and Native Americans, but not present-day Han Chinese.
Ghost Populations
The term "ghost population" is used to describe a population that can be inferred to have existed in the past using statistical reconstruction but that no longer exists in unmixed form. And indeed the bones found in a south-central Siberian grave dating from around 24,000 years ago match the predicted genome of "ancient north Eurasians." The following graphic illustrates the "four population ancestral analysis" that illustrates how the existence of "ancient north Eurasians" was determined.
Sardinians Are Remnant of Early Europeans
It's interesting to note from the above illustration that today's Sardinians are the closest relatives to ancestral Europeans because the mixing with north Eurasians didn't reach them.
Neanderthal Markers in European and Asian DNA
Also of interest from the above illustration is the fact that modern human/Neanderthal mixing occurred with the "ancestral non-Africans" but not with the "predicted ghost population" of ancient north Eurasia. Consequently, present day Han Chinese have a higher percentage of Neanderthal markers in their DNA than present day northern Europeans (4% vs. 2%). This is counter intuitive since the mixing between modern humans and Neanderthal occurred in Europe and the Middle East.
Controversies
The book contains a chapter which discusses some of the controversies caused by the recent advances in genome research. One subject discussed is the refusal of some Native American tribes to allow bones of their ancestors be analyzed. This has developed from a long history of scientists who have shown disrespect to this ethnic group. The author sees this as an unfortunate situation which he hopes can be resolved with time and improved trust between the two sides.
Problems with Racists
Another issue discussed is the problem with those who object to any analysis of differences between human groups because it gives fuel to racists. The author believes that enforcement of artificial political correctness on genome research would allow those of a paranoid disposition to claim that the scientfic community is hiding the "truth." He says it is best to have an open an transparent discussion of genome differences between racial groups.
NYT Article of Interest
The following is a link (not from the book) to an article about an archeological excavation of a grave of a human who was a mixture of Neanderthal and Denisovan, but not modern human.
https://www.nytimes.com/2018/08/22/sc...
Excerpt from Another Book
The following is not from this book. It's a link to an excerpt from Evolving Ourselves by Juan Enriquez and Steve Gullans. I found of particular interest the quote, "There are almost no examples of Neanderthal cavities. Paleolithic and Mesolithic human skulls are almost devoid of cavities." https://t.co/HfAjYUwDoh
June 23, 2021
The idea of an existence of a pure human race is scientifically dead.
Geneticist, David Reich, discovers through the process of whole-genome sequencing that modern humans are a mixture of a variety of human species, where forty thousand years ago our planet was inhabited by multiple groups of archaic humans that were physically different.
Comparing ancient to modern human DNA, Reich finds that the non-African genome, fifty thousand years ago, which was a direct ancestor of modern humans, had almost 5 percent of Neanderthal origin, while non-African genomes today consist of nearly 2 percent of Neanderthal origin. Hence, Neanderthals and the archaic human interbred. This depletion of the Neanderthal genes is accomplished by natural selection, at the expense of the Neanderthals DNA, and perhaps due to the high infertility of this hybrid. A similar history is shared in Asia and Oceania with the Denisovans, where Neanderthals and Denisovans are cousins. With all these findings, can we conclude that modern humans are to some degree biologically different?
Reich's laboratory was able to trace through analyzing the ancient DNA that the people of the Yamnaya culture from the Eurasian Steppe around five thousand years ago migrated to Europe and to a significant degree replaced the majority of the then existing European population. Reich further hypothesizes that this could be evidence why the Northern European languages spoken today are so closely kindred i.e. as a consequence of the spread of a new culture at the same time.
Genomic data also traces that the descendants of Indians today are a mixture of ancestral people of West Eurasia and South and East Asia and that the spreading of the Yamnaya five thousand years ago could offer a clue on how these two regions and their languages are a part of the same Indo-European language family. What was also fascinating is that an Ancient North Eurasian population genetically contributes one-third of their ancestry of present-day Native Americans, while the natives of the Amazon share ancestry with the indigenous people of Australia, New Guinea, and Andaman.
Who We Are and How We Got Here (2018) reconstruct events of the human past that reveals the history of humankind's movements, interbreeding, and transformations, replacement, and extinction of populations. David Reich in my opinion is not quite the writer and storyteller as Siddhartha Mukherjee, hence, the narrative is not as compelling as it is in Mukherjee's The Gene: An Intimate History. On the other hand, Reich is a heavyweight in his field and his work has and will have a great impact on the future work of archaeologists, anthropologists, and linguists. I have been meaning to read this book for some time now, but reading Sense of History's excellent review of the book triggered me to buy and read it, and I am glad I did.
Geneticist, David Reich, discovers through the process of whole-genome sequencing that modern humans are a mixture of a variety of human species, where forty thousand years ago our planet was inhabited by multiple groups of archaic humans that were physically different.
Comparing ancient to modern human DNA, Reich finds that the non-African genome, fifty thousand years ago, which was a direct ancestor of modern humans, had almost 5 percent of Neanderthal origin, while non-African genomes today consist of nearly 2 percent of Neanderthal origin. Hence, Neanderthals and the archaic human interbred. This depletion of the Neanderthal genes is accomplished by natural selection, at the expense of the Neanderthals DNA, and perhaps due to the high infertility of this hybrid. A similar history is shared in Asia and Oceania with the Denisovans, where Neanderthals and Denisovans are cousins. With all these findings, can we conclude that modern humans are to some degree biologically different?
Reich's laboratory was able to trace through analyzing the ancient DNA that the people of the Yamnaya culture from the Eurasian Steppe around five thousand years ago migrated to Europe and to a significant degree replaced the majority of the then existing European population. Reich further hypothesizes that this could be evidence why the Northern European languages spoken today are so closely kindred i.e. as a consequence of the spread of a new culture at the same time.
Genomic data also traces that the descendants of Indians today are a mixture of ancestral people of West Eurasia and South and East Asia and that the spreading of the Yamnaya five thousand years ago could offer a clue on how these two regions and their languages are a part of the same Indo-European language family. What was also fascinating is that an Ancient North Eurasian population genetically contributes one-third of their ancestry of present-day Native Americans, while the natives of the Amazon share ancestry with the indigenous people of Australia, New Guinea, and Andaman.
Who We Are and How We Got Here (2018) reconstruct events of the human past that reveals the history of humankind's movements, interbreeding, and transformations, replacement, and extinction of populations. David Reich in my opinion is not quite the writer and storyteller as Siddhartha Mukherjee, hence, the narrative is not as compelling as it is in Mukherjee's The Gene: An Intimate History. On the other hand, Reich is a heavyweight in his field and his work has and will have a great impact on the future work of archaeologists, anthropologists, and linguists. I have been meaning to read this book for some time now, but reading Sense of History's excellent review of the book triggered me to buy and read it, and I am glad I did.
February 23, 2019
Reich, a Harvard genetics professor, is a leading scientist investigating ancient DNA. He brings us up to date on the significant progress that has been made in the extraction and analysis of DNA from ancient bones. These recent studies change what we know about the movements of prehistoric peoples and our relationships to archaic humans and each other. In 2010 the genomes of only five ancient people had been published. By 2017 over 700 ancient individual genomes had been published with Reich’s laboratory having produced 3,000 more that are unpublished. The success rates of DNA extraction from very old bones has increased dramatically and the cost has declined precipitously as ever more efficient methods have been devised. We are at the beginning of a new era in understanding our deep past.
A traditional way to view human evolution is like the branches of a tree. One population buds off and separates into another but the branches don’t come back together. Reich’s analysis of the genomes of ancient populations shows that modern human prehistory wasn’t at all like that. Mass movement of people from one location to another was common displacing and mixing in varying degrees with the prior inhabitants creating a new genome. With few exceptions ancestors of people in any area came from somewhere else in a process that was repeated time and again. This undercuts simple notions of race as we are all the products of blends on top of blends of diverse peoples.
Examining DNA and its mutations in ancient bones has clarified our relationships to archaic humans, such as Neanderthals and Denisovans. Neanderthals separated from modern human ancestors 550,000-770,000 years ago. Neanderthals dominated Europe 400,000 years ago. Modern humans migrated out of Africa to the Near East 100,000-130,000 years ago. Neanderthals expanded out of Europe westward across Asia and to the Near East after about 100,000 years ago and again 70,000 years ago forcing modern humans to retreat. Then after about 60,000 years ago modern humans predominated in the Near East. Throughout this period there was plenty of opportunity for interbreeding. Current analysis shows modern humans and Neanderthals interbred in the Near East 49,000-54,000 years ago and again later in Europe. Today non-Africans retain 1.5%-2.1% Neanderthal genes with the highest percentage in East and South Asians leading Reich to conclude that most Neanderthal DNA comes from interbreeding in the Near East.
Denisovans were more closely related to Neanderthals than modern humans. Neanderthal and Denisovan populations separated 380,000-470,000 years ago. Migrations in Asia brought Denisovans and modern humans together and analysis shows they interbred about 44,000-49,000 years ago. Asians today have Denisovan genes. The highest percentage is found in the indigenous peoples of New Guinea, Australia and the Philippines. The people of New Guinea have 3%-6% Denisovan genes on top of their 2% Neanderthal genes for up to 8% archaic human genes.
Reich goes on to examine the movement, mixing and replacement of many different populations of modern humans. A fascinating example is that of Native Americans whose DNA is closer to that of Europeans than Asians. How did this happen? Over 15,000 years ago an Ancient North Eurasian population split with one group heading east mixing with East Asians along the way and crossing the Bering Strait. The other group headed west mixing with another population that would many years later populate northern Europe. Today half the people in the world have between 5% and 40% of their genome inherited from these Ancient North Eurasians. Current native Siberians are not primarily related to the ancient group. Today we all are the result of the mixing and remixing of unique peoples that no longer exist.
Since modern humans entered Europe there was continuous cycle of replacement and blending. Reich describes it all but I’ll just keep it to the recent past. Four major groups of people were present in western Eurasia 10,000 years ago: Fertile Crescent farmers, Iranian farmers, eastern European hunter gatherers and western-central European hunter gatherers. Each group was as different from the other as are Europeans and Asians today. Each would have looked like a different race. Then the farmers expanded their territories and blended with outlying populations: Iranian farmers to India, Israeli-Jordanian farmers to east Africa, Turkish farmers to Europe. European hunter gatherers around 8,000 years ago were dark skinned with dark hair and blue eyes. They were largely replaced by migrating Anatolian farmers with light skin, brown eyes and dark hair.
Then 5,000 years ago the Yamnaya people of the eastern European steppes migrated across northern Europe. These violent people had mastered the horse, wheeled carts and a signature battle axe. The Yamnaya are the ancestors of modern day north Europeans. The Yamnaya brought with them blonde hair from a single mutation 17,000 years ago which they acquired from the Ancient North Eurasian population mentioned earlier. The Ancient North Eurasians had also supplied the Yamnaya with the same genes they had contributed to Native Americans. The Yamnaya were cattle herders who also brought with them a form of the plague which analysis indicates killed many of the Europeans they replaced. Also the Yamnaya spread Indo-European language across Europe.
In movements similar to Europe’s around 9,000 years ago Iranian farmers migrated to India mixing with the resident hunter gatherers. Then 5,000 years ago another group of Yamnaya from the central Asian steppes migrated to northern India and blended with the existing inhabitants. They brought Indo-European language and their genes. Southern Indians and lower castes have more of the prior residents’ genome while northern Indians and higher castes, particularly the Brahmins have more from the invaders. Brahmins, the priestly caste, were responsible for the ancient texts written in Old Sanskrit, an Indo-European language. In the south the Dravidian languages continued to predominate. Mitochondrial (female) DNA of all Indians is almost completely from the prior inhabitants. Indians with Yamnaya DNA got it almost exclusively from males. It doesn’t take much to figure this out. European genes in African Americans came primarily from males. European genes in indigenous peoples in the Americas also came disproportionately from males.
In Asia the original out-of-Africa modern humans split with some following the coastline east and island hopping down to Australia, some went to Southeast Asia, some to Mongolia, and some to eastern China with some of those continuing on to the north where they would eventually mix with the migrating Ancient North Eurasian population and cross the Bering Strait. Unfortunately China does not allow ancient remains out of the country. Reich and others in the West cannot perform their advanced techniques to retrieve and analyze the DNA. Thus his China analysis is limited as is that of Native Americans due to U.S. laws requiring tribal approval to test remains. Based on what he has Reich traces two population centers that arose with the advent of farming 9,000 years ago, one on the Yellow River and one to the south on the Yangtze. The Yellow River population expanded west to Tibet and the Yangtze River population spread to Southeast Asia and Taiwan mixing with prior residents. There was a second island hopping migration, this time from from Taiwan 5,000 years ago. They displaced residents of the Philippines and some went onto the Solomon Islands and Fiji, making them the first people on the Southwest Pacific Islands. Another migration by people of Papuan decent followed 2,400 years ago from the Bismarck Islands off New Guinea to the Southwest Islands. More migrations followed.
Africa too experienced migrations and populations disappearing and contributing to new ones. Unfortunately DNA does not hold up as well in tropical climes, limiting how much has been discovered about older populations. However new approaches to DNA extraction are beginning to show results in Africa. With sparse results from the distant past Reich sees evidence of substantial mixing as occurred elsewhere but can’t define the groups with certainty. He is more specific beginning with the expansion of agriculturalists. Bantu speakers 4,000 years ago spread from their West African home on the border of present day Nigeria and Cameroon. They spread their language and culture east and south across sub-Saharan Africa. They developed crops supporting dense populations and began making iron tools 2,500 years ago. Another migration of Nilo-Saharan language speakers who were cattle herders spread their language and culture from Mali to Tanzania. They were likely driven by the expansion of the Saharan desert over the last 5,000 years. There was migration of Near East agriculture and language into North Africa. Khoe-Kwadi speakers in South Africa noted for the use of clicks in their language inherited genes and probably language from an East African herder population that no longer exists.
Reich believes we are just at the beginning of understanding the prehistory of humans. But he is concerned about one difficult problem, that of race. Given the ugly history of the eugenics movement and the misuse of the findings of genetic science by extremists today, people are rightly afraid of how Reich’s work will be used. How do we balance this concern against the benefits of modern genetic analysis? Reich offers the example of being confronted with racial concerns when he proposed research identifying just which African Americans are more prone to prostate cancer. Today we know African Americans have a greater risk of prostate cancer, but Reich believes the risk is not evenly spread among them. Reich wanted to identify the specific African populations the problem genes came from and trace them to American populations, which meant testing many people. So the question becomes how we can talk about genetic differences without invoking race and all the baggage that term carries.
As much as is covered here, it is still just a snapshot of what is in this book. Reich describes many more groups and migrations. Also not in this review are the details Reich supplies of the analytics supporting his assertions, another great reason to pick up this book. What we learn is groundbreaking but he identifies many gaps that need further research. The good news is that the application of these genomic techniques has just begun. It’s less than ten years since the first five ancient genomes were published. I suspect what we will find out in another ten years will be astounding.
A traditional way to view human evolution is like the branches of a tree. One population buds off and separates into another but the branches don’t come back together. Reich’s analysis of the genomes of ancient populations shows that modern human prehistory wasn’t at all like that. Mass movement of people from one location to another was common displacing and mixing in varying degrees with the prior inhabitants creating a new genome. With few exceptions ancestors of people in any area came from somewhere else in a process that was repeated time and again. This undercuts simple notions of race as we are all the products of blends on top of blends of diverse peoples.
Examining DNA and its mutations in ancient bones has clarified our relationships to archaic humans, such as Neanderthals and Denisovans. Neanderthals separated from modern human ancestors 550,000-770,000 years ago. Neanderthals dominated Europe 400,000 years ago. Modern humans migrated out of Africa to the Near East 100,000-130,000 years ago. Neanderthals expanded out of Europe westward across Asia and to the Near East after about 100,000 years ago and again 70,000 years ago forcing modern humans to retreat. Then after about 60,000 years ago modern humans predominated in the Near East. Throughout this period there was plenty of opportunity for interbreeding. Current analysis shows modern humans and Neanderthals interbred in the Near East 49,000-54,000 years ago and again later in Europe. Today non-Africans retain 1.5%-2.1% Neanderthal genes with the highest percentage in East and South Asians leading Reich to conclude that most Neanderthal DNA comes from interbreeding in the Near East.
Denisovans were more closely related to Neanderthals than modern humans. Neanderthal and Denisovan populations separated 380,000-470,000 years ago. Migrations in Asia brought Denisovans and modern humans together and analysis shows they interbred about 44,000-49,000 years ago. Asians today have Denisovan genes. The highest percentage is found in the indigenous peoples of New Guinea, Australia and the Philippines. The people of New Guinea have 3%-6% Denisovan genes on top of their 2% Neanderthal genes for up to 8% archaic human genes.
Reich goes on to examine the movement, mixing and replacement of many different populations of modern humans. A fascinating example is that of Native Americans whose DNA is closer to that of Europeans than Asians. How did this happen? Over 15,000 years ago an Ancient North Eurasian population split with one group heading east mixing with East Asians along the way and crossing the Bering Strait. The other group headed west mixing with another population that would many years later populate northern Europe. Today half the people in the world have between 5% and 40% of their genome inherited from these Ancient North Eurasians. Current native Siberians are not primarily related to the ancient group. Today we all are the result of the mixing and remixing of unique peoples that no longer exist.
Since modern humans entered Europe there was continuous cycle of replacement and blending. Reich describes it all but I’ll just keep it to the recent past. Four major groups of people were present in western Eurasia 10,000 years ago: Fertile Crescent farmers, Iranian farmers, eastern European hunter gatherers and western-central European hunter gatherers. Each group was as different from the other as are Europeans and Asians today. Each would have looked like a different race. Then the farmers expanded their territories and blended with outlying populations: Iranian farmers to India, Israeli-Jordanian farmers to east Africa, Turkish farmers to Europe. European hunter gatherers around 8,000 years ago were dark skinned with dark hair and blue eyes. They were largely replaced by migrating Anatolian farmers with light skin, brown eyes and dark hair.
Then 5,000 years ago the Yamnaya people of the eastern European steppes migrated across northern Europe. These violent people had mastered the horse, wheeled carts and a signature battle axe. The Yamnaya are the ancestors of modern day north Europeans. The Yamnaya brought with them blonde hair from a single mutation 17,000 years ago which they acquired from the Ancient North Eurasian population mentioned earlier. The Ancient North Eurasians had also supplied the Yamnaya with the same genes they had contributed to Native Americans. The Yamnaya were cattle herders who also brought with them a form of the plague which analysis indicates killed many of the Europeans they replaced. Also the Yamnaya spread Indo-European language across Europe.
In movements similar to Europe’s around 9,000 years ago Iranian farmers migrated to India mixing with the resident hunter gatherers. Then 5,000 years ago another group of Yamnaya from the central Asian steppes migrated to northern India and blended with the existing inhabitants. They brought Indo-European language and their genes. Southern Indians and lower castes have more of the prior residents’ genome while northern Indians and higher castes, particularly the Brahmins have more from the invaders. Brahmins, the priestly caste, were responsible for the ancient texts written in Old Sanskrit, an Indo-European language. In the south the Dravidian languages continued to predominate. Mitochondrial (female) DNA of all Indians is almost completely from the prior inhabitants. Indians with Yamnaya DNA got it almost exclusively from males. It doesn’t take much to figure this out. European genes in African Americans came primarily from males. European genes in indigenous peoples in the Americas also came disproportionately from males.
In Asia the original out-of-Africa modern humans split with some following the coastline east and island hopping down to Australia, some went to Southeast Asia, some to Mongolia, and some to eastern China with some of those continuing on to the north where they would eventually mix with the migrating Ancient North Eurasian population and cross the Bering Strait. Unfortunately China does not allow ancient remains out of the country. Reich and others in the West cannot perform their advanced techniques to retrieve and analyze the DNA. Thus his China analysis is limited as is that of Native Americans due to U.S. laws requiring tribal approval to test remains. Based on what he has Reich traces two population centers that arose with the advent of farming 9,000 years ago, one on the Yellow River and one to the south on the Yangtze. The Yellow River population expanded west to Tibet and the Yangtze River population spread to Southeast Asia and Taiwan mixing with prior residents. There was a second island hopping migration, this time from from Taiwan 5,000 years ago. They displaced residents of the Philippines and some went onto the Solomon Islands and Fiji, making them the first people on the Southwest Pacific Islands. Another migration by people of Papuan decent followed 2,400 years ago from the Bismarck Islands off New Guinea to the Southwest Islands. More migrations followed.
Africa too experienced migrations and populations disappearing and contributing to new ones. Unfortunately DNA does not hold up as well in tropical climes, limiting how much has been discovered about older populations. However new approaches to DNA extraction are beginning to show results in Africa. With sparse results from the distant past Reich sees evidence of substantial mixing as occurred elsewhere but can’t define the groups with certainty. He is more specific beginning with the expansion of agriculturalists. Bantu speakers 4,000 years ago spread from their West African home on the border of present day Nigeria and Cameroon. They spread their language and culture east and south across sub-Saharan Africa. They developed crops supporting dense populations and began making iron tools 2,500 years ago. Another migration of Nilo-Saharan language speakers who were cattle herders spread their language and culture from Mali to Tanzania. They were likely driven by the expansion of the Saharan desert over the last 5,000 years. There was migration of Near East agriculture and language into North Africa. Khoe-Kwadi speakers in South Africa noted for the use of clicks in their language inherited genes and probably language from an East African herder population that no longer exists.
Reich believes we are just at the beginning of understanding the prehistory of humans. But he is concerned about one difficult problem, that of race. Given the ugly history of the eugenics movement and the misuse of the findings of genetic science by extremists today, people are rightly afraid of how Reich’s work will be used. How do we balance this concern against the benefits of modern genetic analysis? Reich offers the example of being confronted with racial concerns when he proposed research identifying just which African Americans are more prone to prostate cancer. Today we know African Americans have a greater risk of prostate cancer, but Reich believes the risk is not evenly spread among them. Reich wanted to identify the specific African populations the problem genes came from and trace them to American populations, which meant testing many people. So the question becomes how we can talk about genetic differences without invoking race and all the baggage that term carries.
As much as is covered here, it is still just a snapshot of what is in this book. Reich describes many more groups and migrations. Also not in this review are the details Reich supplies of the analytics supporting his assertions, another great reason to pick up this book. What we learn is groundbreaking but he identifies many gaps that need further research. The good news is that the application of these genomic techniques has just begun. It’s less than ten years since the first five ancient genomes were published. I suspect what we will find out in another ten years will be astounding.
November 20, 2022
David Reich is a Harvard educated geneticist with a keen interest in ancient DNA and how it relates to human migrations and the mixing of populations.
Reich may write with the authority of an Ivy League intellectual, but he projects the enthusiasm of a child at christmas. It is that enthusiasm that propels Reich’s narrative of human evolution, population dispersal, integration and (sometimes) looping reintegration.
“Now that the genome revolution has arrived, with its power to reject longstanding theories, we need to abandon the practice of approaching questions about the human past with strong expectations. To understand who we are, we need to approach the past with humility and with an open mind, and to be ready to change our minds out of respect to the power of hard data.”
Reich has the intestinal fortitude to go where the hard data leads him, even when that data disproves his own theories, because that is how science (real science) works. This is not a fluff piece of conjecture and speculation (if it’s conjecture you’re craving, Reich suggests A Troublesome Inheritance by journalist Nicholas Wade). ‘Archaeogenetics’ is a science still in its infancy, but it is building a database that has already brought new and unexpected perspectives to anthropology and archeology. Old paradigms are being challenged, new ones are being formulated, change is inevitable. Even this book, first published in 2018, is already in need of revision. If you’re a science nerd like me, these are exciting times.
Reich may write with the authority of an Ivy League intellectual, but he projects the enthusiasm of a child at christmas. It is that enthusiasm that propels Reich’s narrative of human evolution, population dispersal, integration and (sometimes) looping reintegration.
“Now that the genome revolution has arrived, with its power to reject longstanding theories, we need to abandon the practice of approaching questions about the human past with strong expectations. To understand who we are, we need to approach the past with humility and with an open mind, and to be ready to change our minds out of respect to the power of hard data.”
Reich has the intestinal fortitude to go where the hard data leads him, even when that data disproves his own theories, because that is how science (real science) works. This is not a fluff piece of conjecture and speculation (if it’s conjecture you’re craving, Reich suggests A Troublesome Inheritance by journalist Nicholas Wade). ‘Archaeogenetics’ is a science still in its infancy, but it is building a database that has already brought new and unexpected perspectives to anthropology and archeology. Old paradigms are being challenged, new ones are being formulated, change is inevitable. Even this book, first published in 2018, is already in need of revision. If you’re a science nerd like me, these are exciting times.
July 2, 2018
Such fascinating science and research on ancient DNA. I also really loved all the research about the Iranian Nomad populations that are basically the tribe that took over Europe because those are my people (kind of because there was a lot of mixing). It was also stunning to see how inequality and male domination affected genetics. Basically a few really powerful men who spread their DNA far and wide. Women obviously can't have too many children, but also history seems to be just conquering armies of men spreading their seeds over conquered populations of women.
He also talks at the end about race differences and how we should be prepared to deal with what advanced DNA science will have to say about that. I think he's a bit more confident than his data can take him. I think the DNA stuff is obviously clear to him, but he's not an IQ scientist and I think most people who study cognitive testing believe that it is far from being scientifically rigorous or rooted in genetic differences. In other words, we haven't been able to separate genetics from environment when it comes to cognitive ability. Reich may be confident he can parse out modern races from their DNA, but I do worry about trying to plot races on cognitive factors. By all means, we should look at diseases and all sorts of stuff that have clear genetic variants, but before we start talking about intelligence, we better make sure the science on that is air tight.
He also talks at the end about race differences and how we should be prepared to deal with what advanced DNA science will have to say about that. I think he's a bit more confident than his data can take him. I think the DNA stuff is obviously clear to him, but he's not an IQ scientist and I think most people who study cognitive testing believe that it is far from being scientifically rigorous or rooted in genetic differences. In other words, we haven't been able to separate genetics from environment when it comes to cognitive ability. Reich may be confident he can parse out modern races from their DNA, but I do worry about trying to plot races on cognitive factors. By all means, we should look at diseases and all sorts of stuff that have clear genetic variants, but before we start talking about intelligence, we better make sure the science on that is air tight.
July 10, 2022
In this review I'm focussing on the revolutionary new insights that the research of fossil DNA or ancient DNA has yielded so far in the domain of the human past. Actually, this comes with a hefty warning, because in this book David Reich especially highlights the merits of this research - which is his right as a pioneer in this field - but only sporadically touches on its limitations. I zoomed in on these limitations in my general account on Goodreads (see https://www.goodreads.com/review/show...).
Anyway, what is the revolutionary thing that we have learned so far from this ancient DNA research? It turns out that this extends to three domains: the lineage of the human species (modern sapiens) in relation to other hominids, the geographic and biological migration between populations within the sapiens species, and finally the living conditions of those populations. That's not nothing, indeed.
The first aspect is rightly called by Reich "the deep history of our species": where does the sapiens species come from? How did it evolve from a lineage that traces us back to a common ancestor with great apes? Here, if you read Reich carefully, ancient DNA turns out not to be able to contribute that much, at least not for the time being. Through normal genetic research on people living today, some generalities can be distilled about jumps in the lineage, but they are accompanied by very large chronological margins. Ancient DNA research reduces those margins, because the genetic traces of older hominids are of course more evident in people who lived further back in time (certain early mutations become less prominent because of the mixing of populations). But for the time being, this has only made the picture more complex: in addition to the already known archaeological-based species such as australopithecus, homo erectus and others, a lot of "ghost populations" are now emerging. This may be clarified in the future, but chances are that we will never be able to reconstruct the full picture.
A surprising find is that a-DNA research apparently both confirms ànd unsettles the "Out-of-Africa" theory, or at least nuances it. Initial genetic research seemed to have confirmed the old these that the sapiens species originated in Africa and conquered the world from there, just as all other older species would have originated in Africa. But the thesis of Africa as the unique factory of hominids now turns out to be a bit too simplistic. Reich points out that there are strong suspicions that the sapiens species may have evolved from the admixture of older species that returned to Africa and mingled there with other more evolved African species, somewhere between 500 and 300,000 years ago, in that process producing the earliest sapiens. I know, this sounds complicated, and much of what Reich writes has a very theoretical content (so again with a lot of "ghost populations"), which should prompt us to be very cautious. There’s no doubt however that the most decisive and widespread migration out of Africa took place around 50.000 years ago, and this more modern version of sapiens eventually spread throughout the rest of the world.
There is a second domain in which a-DNA research provides new insights, and that is that of the migration movements of the sapiens species, roughly for the last 100,000 years (the period for which it is still relatively easy to extract old DNA from the fossils ). From the account that Reich gives about this, can be deduced that in this domain the discoveries are indeed revolutionary and call into question a lot of old theories based on classical archeology. This relates to, for instance, the complicated issue about the influx of modern people into the American continent, but even more so to the different migration movements in Europe. Here, among other things, the question of the mixing with the Neanderthal species (actually, species is the wrong term) comes up: genetic research already in 2012 proved with certainty that this interbreeding really happened. But even more relevant is the influx of early farmers into Europe: a-DNA research shows that it happened about 8,000 years ago from a population living in Anatolia (present-day Turkey), and that almost all older hunter-gatherers were wiped off the map (more in one area than in another). But the big surprise is that a little later, around 5,000 years ago, there was an even greater influx of pastoral nomads from southern Russia and Central Asia, and that their genome now dominates almost all populations of Europe. What bothered me is that Reich quite affirmatively links these movements with data from classical archeology (the sequence of cultures named after the typical pottery they produced); his story on this point seems a bit too simplistic and rather over-interpretative here.
Anyway, what is clear is that just about every population today is the fruit of constant interbreeding, migratory flows back and forth, on a large and small scale, and that as a consequence simplistic categories like "race" have no real biological relevance. However, it is striking that Reich does plead for caution here and unlike many of his colleagues keeps the door ajar. Without being concrete he does not rule out the possibility that future genetic research will demonstrate biological differences, going against the stiffling orthodoxy in academics after World War II. Reich pleads to properly frame these findings: “we need to come up with a new way of thinking that can accommodate such differences, rather than deny categorically that differences can exist and so find ourselves caught without a strategy once they are found.” I think this is a healthy attitude, but I still find it odd that Reich brings this up without making his indications concrete.
The final domain where a-DNA research is yielding new insights is surprisingly enough in the social relationships between and within earlier populations. You wouldn't expect it, but DNA research of fossils can reveal whether a migration flow in the distant past was accompanied by violence or instilled social inequality. A typical example is the Dzenghis Khan line, which can be identified through research on the (male) Y chromosome and now represents 8% of the genetic material in men in the areas that were under Mongol control. But there are also such indications further back in time: the Y chromosome of men from the Central Asian steppe region about 5,000 years ago is much more clearly present in 'subdued' populations in Europe: “in this period, it began to be possible for single males to accumulate so much power that they could not only gain access to large numbers of females, but they could also pass on their social prestige to subsequent generations and ensure that their male descendants were similarly successful. This process caused the Y chromosomes these males carried to increase in frequency generation after generation, leaving a genetic scar that speaks volumes about past societies.”
This example indeed shows that a lot more can be deduced from the reading of the genome than you might think at first glance. Still, again I would like to end with a warning. If you read Reich's book carefully, you will notice that many of his claims still are very speculative theories that are not yet supported by empirical evidence. A-DNA research is a fascinating and promising new branch of historical science, for sure, but it would be wrong to expect too much from it, or to refrain from a healthy critical stance.
rating 3.5 stars
Anyway, what is the revolutionary thing that we have learned so far from this ancient DNA research? It turns out that this extends to three domains: the lineage of the human species (modern sapiens) in relation to other hominids, the geographic and biological migration between populations within the sapiens species, and finally the living conditions of those populations. That's not nothing, indeed.
The first aspect is rightly called by Reich "the deep history of our species": where does the sapiens species come from? How did it evolve from a lineage that traces us back to a common ancestor with great apes? Here, if you read Reich carefully, ancient DNA turns out not to be able to contribute that much, at least not for the time being. Through normal genetic research on people living today, some generalities can be distilled about jumps in the lineage, but they are accompanied by very large chronological margins. Ancient DNA research reduces those margins, because the genetic traces of older hominids are of course more evident in people who lived further back in time (certain early mutations become less prominent because of the mixing of populations). But for the time being, this has only made the picture more complex: in addition to the already known archaeological-based species such as australopithecus, homo erectus and others, a lot of "ghost populations" are now emerging. This may be clarified in the future, but chances are that we will never be able to reconstruct the full picture.
A surprising find is that a-DNA research apparently both confirms ànd unsettles the "Out-of-Africa" theory, or at least nuances it. Initial genetic research seemed to have confirmed the old these that the sapiens species originated in Africa and conquered the world from there, just as all other older species would have originated in Africa. But the thesis of Africa as the unique factory of hominids now turns out to be a bit too simplistic. Reich points out that there are strong suspicions that the sapiens species may have evolved from the admixture of older species that returned to Africa and mingled there with other more evolved African species, somewhere between 500 and 300,000 years ago, in that process producing the earliest sapiens. I know, this sounds complicated, and much of what Reich writes has a very theoretical content (so again with a lot of "ghost populations"), which should prompt us to be very cautious. There’s no doubt however that the most decisive and widespread migration out of Africa took place around 50.000 years ago, and this more modern version of sapiens eventually spread throughout the rest of the world.
There is a second domain in which a-DNA research provides new insights, and that is that of the migration movements of the sapiens species, roughly for the last 100,000 years (the period for which it is still relatively easy to extract old DNA from the fossils ). From the account that Reich gives about this, can be deduced that in this domain the discoveries are indeed revolutionary and call into question a lot of old theories based on classical archeology. This relates to, for instance, the complicated issue about the influx of modern people into the American continent, but even more so to the different migration movements in Europe. Here, among other things, the question of the mixing with the Neanderthal species (actually, species is the wrong term) comes up: genetic research already in 2012 proved with certainty that this interbreeding really happened. But even more relevant is the influx of early farmers into Europe: a-DNA research shows that it happened about 8,000 years ago from a population living in Anatolia (present-day Turkey), and that almost all older hunter-gatherers were wiped off the map (more in one area than in another). But the big surprise is that a little later, around 5,000 years ago, there was an even greater influx of pastoral nomads from southern Russia and Central Asia, and that their genome now dominates almost all populations of Europe. What bothered me is that Reich quite affirmatively links these movements with data from classical archeology (the sequence of cultures named after the typical pottery they produced); his story on this point seems a bit too simplistic and rather over-interpretative here.
Anyway, what is clear is that just about every population today is the fruit of constant interbreeding, migratory flows back and forth, on a large and small scale, and that as a consequence simplistic categories like "race" have no real biological relevance. However, it is striking that Reich does plead for caution here and unlike many of his colleagues keeps the door ajar. Without being concrete he does not rule out the possibility that future genetic research will demonstrate biological differences, going against the stiffling orthodoxy in academics after World War II. Reich pleads to properly frame these findings: “we need to come up with a new way of thinking that can accommodate such differences, rather than deny categorically that differences can exist and so find ourselves caught without a strategy once they are found.” I think this is a healthy attitude, but I still find it odd that Reich brings this up without making his indications concrete.
The final domain where a-DNA research is yielding new insights is surprisingly enough in the social relationships between and within earlier populations. You wouldn't expect it, but DNA research of fossils can reveal whether a migration flow in the distant past was accompanied by violence or instilled social inequality. A typical example is the Dzenghis Khan line, which can be identified through research on the (male) Y chromosome and now represents 8% of the genetic material in men in the areas that were under Mongol control. But there are also such indications further back in time: the Y chromosome of men from the Central Asian steppe region about 5,000 years ago is much more clearly present in 'subdued' populations in Europe: “in this period, it began to be possible for single males to accumulate so much power that they could not only gain access to large numbers of females, but they could also pass on their social prestige to subsequent generations and ensure that their male descendants were similarly successful. This process caused the Y chromosomes these males carried to increase in frequency generation after generation, leaving a genetic scar that speaks volumes about past societies.”
This example indeed shows that a lot more can be deduced from the reading of the genome than you might think at first glance. Still, again I would like to end with a warning. If you read Reich's book carefully, you will notice that many of his claims still are very speculative theories that are not yet supported by empirical evidence. A-DNA research is a fascinating and promising new branch of historical science, for sure, but it would be wrong to expect too much from it, or to refrain from a healthy critical stance.
rating 3.5 stars
January 22, 2019
‘The speed at which the ancient DNA revolution is moving is exhilarating. The technology is evolving so quickly that many papers being published right now use methods that will be obsolete within a few years.’
Without having any special knowledge of genomics, anthropology or archeology, I am not well placed to review this book. Therefore, what follows is just my impressions and main take from it. Admirably, Reich’s book is not Eurocentric, it covers all the regions to some extent. But mine notes focus more on Europe just because i live here.
The book is about the breakthrough in a relatively new field - Ancient Genomics which analyses the ancient DNA in order to study how the genetic make up of modern people and their ancestors affected history. The potential investigative power of DNA for historic research was envisaged in the 60s of the last century. But only in the last 5 years or so this area has leaped forward dramatically. So, the book summarises the cutting age research, mainly derived from Reich’s lab and from his collaborations, the science in flux, not the result of the common consensus. This as well as Reich background as geneticist, needs to be taken into the account while reading it, but the book is well written, entertaining and revelatory. Moreover, in many ways it disrupts the consensus about the evolution of ancient human populations. The consensus, which existed in pre-history almost up until 2012.
The research covers ancient populations and their movements around the globe since first humans and up to circa 4000 years ago (a bit later for Africa). So it does not go up to the modern time. But Reich states that for Eurasia for example, including India, the genetic make-up of people 4 thousands years ago is close to the modern make up across the high level population’s clusters such as the West and East Eurasians for example. It was certainly not the case for the earlier periods when the mixtures were very different. The book covers all significant regions such as Western and Eastern Eurasia, Australia, America, Africa and India.
So what the analyses of the samples of ancient people’s genome tells us according to Reich?
Main result
Until 2012 it was generally accepted that the evolution of the ancient population could be modelled by a tree in which “today’s populations have remained unchanged and separate since branching from a central trunk” after migrating from Africa and, later, after the farmers from Anatolia and Middle East migrated our of their regions. But DNA research has revealed that “this model is dead and that instead the truth has involved great cycles of population separation and mixture". So even 4 thousands years ago there were no such thing as a “purity” of blood or any populations which were not significantly mixed with the other.
Very ancient days
There is certainly genetic evidence that modern-humans and Neanderthals interbreed. But Neanderthals’ genetic inheritance has been decreased by natural selection as their genes seem to be toxic for many parts of modern human genome. It has got adverse affect on male’s fertility for Y-chromosome carrier. On another matter, it does not seem to be the evidence of a “switch gene” - the part of DNA sequence which while evolved in pre-history made people to obtain the language in a one-off development.
Europe
South Europe seems to keep a lot of inheritance from the Middle Eastern and Anatolian farmers (the highest correlation is with the modern Sardinian population). But for the Northern Europe (France, Germany, Britain and alike) the story is more complicated:
First, “Between six thousand and five thousand years ago, most of the northern gene pool was overtaken by farmer ancestry, and it was this mixture of a modest amount of hunter-gatherer-related ancestry and a large amount of Anatolian farmer–related ancestry—in a population that retained key elements of hunter-gatherer culture—that characterized the Funnel Beaker potters and many other contemporary Europeans. Europe had reached a new equilibrium. The people of the Funnel Beaker culture were among those who built megaliths, the collective burial tombs made of stones so large it would have taken dozens of people to move them. The archaeologist Colin Renfrew suggested that megalith building might be a direct reflection of this boundary between southern farmers and hunter-gatherers turned farmers—a way of laying claim to territory, of distinguishing one people and culture from others. The genetic data may bear witness to this interaction, as there was clearly a stream of new migrants into the mixed population. The unmixed hunter-gatherers were disappearing, persisting only in isolated pockets like the islands off southern Sweden.
In remote Britain, the megalith builders were hard at work on what developed into the greatest man-made monument the world had seen: the standing stones of Stonehenge, which became a national place of pilgrimage as reflected by goods brought from the far corners of Britain. People like those at Stonehenge were building great temples to their gods, and tombs for their dead, and could not have known that within a few hundred years their descendants would be gone and their lands overrun.”
Then, somewhere between 4.5 thousands years ago and 4 thousands years ago. The people from the steppe have migrated into Northern Europe in mass and within few hundreds years mixed and/or replaced the local populations to such an extent that they are now “primary ancestors of the modern population”. For example 90% Neolithic Britons (those ones who built Stonehenge) were replaced with this mixture. These steppe people were the Yamnaya, by itself the mixture of Iranian and Armenian populations spreading from the coast of the Black and Caspian sea. They were the first people in Eurasia using the wheel, the horse and wagon which made them very mobile. It is unclear how they were so effective in replacing the existent population. But the one theory is bubonic plague to which they were more immune. They brought it with them. Reich finds it ironic that the earlier Europeans might have been the victims of a similar fate the later Europeans inflicted on the Native Americans in the later history.
The first evidence of Yamaya migration is found in the Corded Ware culture. It is notorious by the fact that it helped the Nazis with their theories. They thought the Germanic people went East with this culture and laid their territorial claim for the Eastern Europe on that basis. The DNA study revealed just the opposite, the Corded wire culture reflected a mass migration of Yamnaya people into the central Europe from the steppe:
“But the genetics showed that the connection between the Corded Ware culture and the Yamnaya culture reflected major movements of people. The makers of the Corded Ware culture were, at least in a genetic sense, a westward extension of the Yamnaya. Our finding about the genetic link between the Yamnaya and the Corded Ware culture demonstrates the disruptive power of ancient DNA. It can prove past movements of people, and in this case has documented a magnitude of population replacement that no modern archaeologist, even the most ardent supporter of migrations, had dared to propose. The association between steppe genetic ancestry and people assigned to the Corded Ware archaeological culture through graves and artifacts is not simply a hypothesis. It is now a proven fact.”
The famous Russian symbolist Alexander Blok in 1918 has written a poem in which he said: “We are all Scythians” (the later people of the same steppe). He might have been right at the end.
There is also a hypothesis that Yamnaya people were the first who spoke Indo-European language which they spread with them both to the West and to India.
India
The population of India is in fact a set of numerous fairly genetically distinct small populations which do not mix with each other very much. Endogamy have been practised in South Asia for thousands years. And the theory that the British has substantially boosted the cast system by actively encouraging non-mixing between the casts during the colonisation has been disapproved by genetic evidence (as far as I understood the argument).
But no-one in India could claim a genetic purity either. There is an evidence of substantial West Eurasian incursion, possibly through Yamnaya as well or the related people (the male line only). But when Reich tried to discuss it with his indian colleagues, “They did not want to be part of a study that suggested a major West Eurasian incursion into India without being absolutely certain as to how the whole-genome data could be reconciled with their mitochondrial DNA findings. They also implied that the suggestion of a migration from West Eurasia would be politically explosive. They did not explicitly say this, but it had obvious overtones of the idea that migration from outside India had a transformative effect on the subcontinent.
We wrote that the people of India today are the outcome of mixtures between two highly differentiated populations, “Ancestral North Indians” (ANI) and “Ancestral South Indians” (ASI), who before their mixture were as different from each other as Europeans and East Asians are today. The ANI are related to Europeans, central Asians, Near Easterners, and people of the Caucasus, but we made no claim about the location of their homeland or any migrations. The ASI descend from a population not related to any present-day populations outside India. We showed that the ANI and ASI had mixed dramatically in India. The result is that everyone in mainland India today is a mix, albeit in different proportions, of ancestry related to West Eurasians, and ancestry more closely related to diverse East Asian and South Asian populations. No group in India can claim genetic purity.”
Controversies
As Reich has got the background in medical genetics, he might come across as not paying sufficient attention to certain ethnic and cultural sensitivities. I personally think that in some areas he is brave enough not to avoid those topics all together. But I could see that some people might find him too direct. And certainly he might cause a lot of disagreements if ethical applications of if his statements would be taken further. Two examples:
- some Native American tribe councils do not allow the tribe members to provide DNA for scientific research even for medical reasons. This ban acts even in the cases if a person involved signs the individual consent form. Reich thinks it might be more harmful than good.
- biological differences across the populations. Here it is getting quite complicated because people associate those high level populations like East Asians, Europeans, Africans etc with race. The race is very charged word for variety of reasons and more appropriate in the conversations about social constructs and their devastating consequences on the society. So Reich is careful showing the difference between the terms of “race” and “population”. However, Reich states that the biological differences across the populations do exist. And sooner or later some differences between the traits and cognitive capabilities might be found as well. Those differences might be smaller that the differences within populations, but still significant. His view that the society should be prepared to discuss this situation.
“What real differences do we know about? We cannot deny the existence of substantial average genetic differences across populations, not just in traits such as skin colour, but also in bodily dimensions, the ability to efficiently digest starch or milk sugar, the ability to breathe easily at high altitudes, and susceptibility to particular diseases. These differences are just the beginning. I expect that the reason we don’t know about a much larger number of differences among human populations is that studies with adequate statistical power to detect them have not yet been carried out.
If selection on height and infant head circumference (across the populations) can occur within a couple of thousand years, it seems a bad bet to argue that there cannot be similar average differences in cognitive or behavioural traits. Even if we do not yet know what the differences are, we should prepare our science and our society to be able to deal with the reality of differences instead of sticking our heads in the sand and pretending that differences cannot be discovered. If as scientists we wilfully abstain from laying out a rational framework for discussing human differences, we will leave a vacuum that will be filled by pseudoscience, an outcome that is far worse than anything we could achieve by talking openly. We will need to deal with these studies and react responsibly to them when they are published, but we can already be sure that we will be surprised by some of the outcomes. The right way to deal with the inevitable discovery of substantial differences across populations is to realize that their existence should not affect the way we conduct ourselves. As a society we should commit to according everyone equal rights despite the differences that exist among individuals. We aspire to treat all individuals with respect regardless of the extraordinary differences that exist among individuals within a population, it should not be so much more of an effort to accommodate the smaller but still significant average differences across populations.”
Some of these points might be debatable and certainly might be emotionally charged for many people. They are discussed in the one of the last chapters of the book. I hope this discussion would not distract the general public and the scientific community from the main findings and the substantial break-through in the the ancient DNA research which is presented in this book.
Without having any special knowledge of genomics, anthropology or archeology, I am not well placed to review this book. Therefore, what follows is just my impressions and main take from it. Admirably, Reich’s book is not Eurocentric, it covers all the regions to some extent. But mine notes focus more on Europe just because i live here.
The book is about the breakthrough in a relatively new field - Ancient Genomics which analyses the ancient DNA in order to study how the genetic make up of modern people and their ancestors affected history. The potential investigative power of DNA for historic research was envisaged in the 60s of the last century. But only in the last 5 years or so this area has leaped forward dramatically. So, the book summarises the cutting age research, mainly derived from Reich’s lab and from his collaborations, the science in flux, not the result of the common consensus. This as well as Reich background as geneticist, needs to be taken into the account while reading it, but the book is well written, entertaining and revelatory. Moreover, in many ways it disrupts the consensus about the evolution of ancient human populations. The consensus, which existed in pre-history almost up until 2012.
The research covers ancient populations and their movements around the globe since first humans and up to circa 4000 years ago (a bit later for Africa). So it does not go up to the modern time. But Reich states that for Eurasia for example, including India, the genetic make-up of people 4 thousands years ago is close to the modern make up across the high level population’s clusters such as the West and East Eurasians for example. It was certainly not the case for the earlier periods when the mixtures were very different. The book covers all significant regions such as Western and Eastern Eurasia, Australia, America, Africa and India.
So what the analyses of the samples of ancient people’s genome tells us according to Reich?
Main result
Until 2012 it was generally accepted that the evolution of the ancient population could be modelled by a tree in which “today’s populations have remained unchanged and separate since branching from a central trunk” after migrating from Africa and, later, after the farmers from Anatolia and Middle East migrated our of their regions. But DNA research has revealed that “this model is dead and that instead the truth has involved great cycles of population separation and mixture". So even 4 thousands years ago there were no such thing as a “purity” of blood or any populations which were not significantly mixed with the other.
Very ancient days
There is certainly genetic evidence that modern-humans and Neanderthals interbreed. But Neanderthals’ genetic inheritance has been decreased by natural selection as their genes seem to be toxic for many parts of modern human genome. It has got adverse affect on male’s fertility for Y-chromosome carrier. On another matter, it does not seem to be the evidence of a “switch gene” - the part of DNA sequence which while evolved in pre-history made people to obtain the language in a one-off development.
Europe
South Europe seems to keep a lot of inheritance from the Middle Eastern and Anatolian farmers (the highest correlation is with the modern Sardinian population). But for the Northern Europe (France, Germany, Britain and alike) the story is more complicated:
First, “Between six thousand and five thousand years ago, most of the northern gene pool was overtaken by farmer ancestry, and it was this mixture of a modest amount of hunter-gatherer-related ancestry and a large amount of Anatolian farmer–related ancestry—in a population that retained key elements of hunter-gatherer culture—that characterized the Funnel Beaker potters and many other contemporary Europeans. Europe had reached a new equilibrium. The people of the Funnel Beaker culture were among those who built megaliths, the collective burial tombs made of stones so large it would have taken dozens of people to move them. The archaeologist Colin Renfrew suggested that megalith building might be a direct reflection of this boundary between southern farmers and hunter-gatherers turned farmers—a way of laying claim to territory, of distinguishing one people and culture from others. The genetic data may bear witness to this interaction, as there was clearly a stream of new migrants into the mixed population. The unmixed hunter-gatherers were disappearing, persisting only in isolated pockets like the islands off southern Sweden.
In remote Britain, the megalith builders were hard at work on what developed into the greatest man-made monument the world had seen: the standing stones of Stonehenge, which became a national place of pilgrimage as reflected by goods brought from the far corners of Britain. People like those at Stonehenge were building great temples to their gods, and tombs for their dead, and could not have known that within a few hundred years their descendants would be gone and their lands overrun.”
Then, somewhere between 4.5 thousands years ago and 4 thousands years ago. The people from the steppe have migrated into Northern Europe in mass and within few hundreds years mixed and/or replaced the local populations to such an extent that they are now “primary ancestors of the modern population”. For example 90% Neolithic Britons (those ones who built Stonehenge) were replaced with this mixture. These steppe people were the Yamnaya, by itself the mixture of Iranian and Armenian populations spreading from the coast of the Black and Caspian sea. They were the first people in Eurasia using the wheel, the horse and wagon which made them very mobile. It is unclear how they were so effective in replacing the existent population. But the one theory is bubonic plague to which they were more immune. They brought it with them. Reich finds it ironic that the earlier Europeans might have been the victims of a similar fate the later Europeans inflicted on the Native Americans in the later history.
The first evidence of Yamaya migration is found in the Corded Ware culture. It is notorious by the fact that it helped the Nazis with their theories. They thought the Germanic people went East with this culture and laid their territorial claim for the Eastern Europe on that basis. The DNA study revealed just the opposite, the Corded wire culture reflected a mass migration of Yamnaya people into the central Europe from the steppe:
“But the genetics showed that the connection between the Corded Ware culture and the Yamnaya culture reflected major movements of people. The makers of the Corded Ware culture were, at least in a genetic sense, a westward extension of the Yamnaya. Our finding about the genetic link between the Yamnaya and the Corded Ware culture demonstrates the disruptive power of ancient DNA. It can prove past movements of people, and in this case has documented a magnitude of population replacement that no modern archaeologist, even the most ardent supporter of migrations, had dared to propose. The association between steppe genetic ancestry and people assigned to the Corded Ware archaeological culture through graves and artifacts is not simply a hypothesis. It is now a proven fact.”
The famous Russian symbolist Alexander Blok in 1918 has written a poem in which he said: “We are all Scythians” (the later people of the same steppe). He might have been right at the end.
There is also a hypothesis that Yamnaya people were the first who spoke Indo-European language which they spread with them both to the West and to India.
India
The population of India is in fact a set of numerous fairly genetically distinct small populations which do not mix with each other very much. Endogamy have been practised in South Asia for thousands years. And the theory that the British has substantially boosted the cast system by actively encouraging non-mixing between the casts during the colonisation has been disapproved by genetic evidence (as far as I understood the argument).
But no-one in India could claim a genetic purity either. There is an evidence of substantial West Eurasian incursion, possibly through Yamnaya as well or the related people (the male line only). But when Reich tried to discuss it with his indian colleagues, “They did not want to be part of a study that suggested a major West Eurasian incursion into India without being absolutely certain as to how the whole-genome data could be reconciled with their mitochondrial DNA findings. They also implied that the suggestion of a migration from West Eurasia would be politically explosive. They did not explicitly say this, but it had obvious overtones of the idea that migration from outside India had a transformative effect on the subcontinent.
We wrote that the people of India today are the outcome of mixtures between two highly differentiated populations, “Ancestral North Indians” (ANI) and “Ancestral South Indians” (ASI), who before their mixture were as different from each other as Europeans and East Asians are today. The ANI are related to Europeans, central Asians, Near Easterners, and people of the Caucasus, but we made no claim about the location of their homeland or any migrations. The ASI descend from a population not related to any present-day populations outside India. We showed that the ANI and ASI had mixed dramatically in India. The result is that everyone in mainland India today is a mix, albeit in different proportions, of ancestry related to West Eurasians, and ancestry more closely related to diverse East Asian and South Asian populations. No group in India can claim genetic purity.”
Controversies
As Reich has got the background in medical genetics, he might come across as not paying sufficient attention to certain ethnic and cultural sensitivities. I personally think that in some areas he is brave enough not to avoid those topics all together. But I could see that some people might find him too direct. And certainly he might cause a lot of disagreements if ethical applications of if his statements would be taken further. Two examples:
- some Native American tribe councils do not allow the tribe members to provide DNA for scientific research even for medical reasons. This ban acts even in the cases if a person involved signs the individual consent form. Reich thinks it might be more harmful than good.
- biological differences across the populations. Here it is getting quite complicated because people associate those high level populations like East Asians, Europeans, Africans etc with race. The race is very charged word for variety of reasons and more appropriate in the conversations about social constructs and their devastating consequences on the society. So Reich is careful showing the difference between the terms of “race” and “population”. However, Reich states that the biological differences across the populations do exist. And sooner or later some differences between the traits and cognitive capabilities might be found as well. Those differences might be smaller that the differences within populations, but still significant. His view that the society should be prepared to discuss this situation.
“What real differences do we know about? We cannot deny the existence of substantial average genetic differences across populations, not just in traits such as skin colour, but also in bodily dimensions, the ability to efficiently digest starch or milk sugar, the ability to breathe easily at high altitudes, and susceptibility to particular diseases. These differences are just the beginning. I expect that the reason we don’t know about a much larger number of differences among human populations is that studies with adequate statistical power to detect them have not yet been carried out.
If selection on height and infant head circumference (across the populations) can occur within a couple of thousand years, it seems a bad bet to argue that there cannot be similar average differences in cognitive or behavioural traits. Even if we do not yet know what the differences are, we should prepare our science and our society to be able to deal with the reality of differences instead of sticking our heads in the sand and pretending that differences cannot be discovered. If as scientists we wilfully abstain from laying out a rational framework for discussing human differences, we will leave a vacuum that will be filled by pseudoscience, an outcome that is far worse than anything we could achieve by talking openly. We will need to deal with these studies and react responsibly to them when they are published, but we can already be sure that we will be surprised by some of the outcomes. The right way to deal with the inevitable discovery of substantial differences across populations is to realize that their existence should not affect the way we conduct ourselves. As a society we should commit to according everyone equal rights despite the differences that exist among individuals. We aspire to treat all individuals with respect regardless of the extraordinary differences that exist among individuals within a population, it should not be so much more of an effort to accommodate the smaller but still significant average differences across populations.”
Some of these points might be debatable and certainly might be emotionally charged for many people. They are discussed in the one of the last chapters of the book. I hope this discussion would not distract the general public and the scientific community from the main findings and the substantial break-through in the the ancient DNA research which is presented in this book.
July 10, 2022
Rating 3.5 stars. It is obvious that genetic research has brought about a complete revolution in the medical world in recent decades. But it is sometimes overlooked that genetics has also turned the historical world upside down. This was done by intensive research on ancient fossils, of humans, animals and plants. Shortly before 2010 it became possible to extract a limited amount of DNA from those fossils, to read out their genome sequences and compare them with others. By examining both the number and the specific place of mutations within that ancient DNA, it is possible to identify lines of kinship or divergence, and thus get a better picture of the populations of millennia ago and their movement across our planet. A well-known example is the presence of a striking portion of Neanderthal DNA in the present inhabitants of Europe and Asia, and also the discovery of another extinct human species, the Denisova, of which hereditary traces can be found especially in Southeast Asia and Oceania.
David Reich portrays this clearly and in great detail, and with authority, because he is one of the pioneers in this field. With his own laboratory in Cambridge, Ma., he is at the forefront of this fast-growing field of the Ancient DNA revolution. His expertise is indisputable, but it also gives this book a certain amount of technicality, making it at times a bit difficult for the layman to follow his train of thought. And as an interested party, Reich naturally stresses the great merits of ancient genetic research, and rightly so, but I want to warn against overestimation, because there are considerable limitations to this kind of research.
In the first place, it is extremely difficult to find usable DNA within fossils: DNA breaks down with time, and all the more in warm and humid areas. The consequence of this is that it is currently very difficult to extract DNA from fossils older than 100,000 years, or from areas that are tropical. Obviously this gives a bias. Reich himself admits that 90% of all fossils examined up to the end of 2017 come from western Eurasia; if that's not an imbalance, then I don't know. Perhaps this will be corrected over time (China is in the process of catching up), but still.
Moreover, the total number of fossils investigated is still relatively limited, and the techniques used are in full development. Genetics and certainly Ancient Genetics is a relatively young science, and so you can see that in this book Reich has to radically contradict findings that were published in scientific journals even as recent as 2010. This should encourage vigilance and (healthy) skepticism. On top of that, it turns out that the interpretation of genetic research is always a statistical thing, in other words genetics is a probabilistic science, and so caution is all the more necessary.
Very little of this is noticeable in this book. Reich seems to be the typical example of a scientist who mainly sees the possibilities/opportunities and who remains fundamentally optimistic about revolutionary new insights and techniques. To some extent his pride is justified, for the new discoveries certainly are impressive. But it is best for anyone reading this book to remember that Reich's presentation - however fascinating - is a preliminary state of affairs, of a new science that is constantly evolving.
Finally, there is the fundamental debate to what extent genetic material can be used to derive a complete picture of human history. Of course it cannot. Genetic material teaches us revolutionary new things about when and where human populations emerged, how they related to each other, and it also offers, in part, insight into social relationships, nutrition and diseases. But the entire world of human culture in the broadest sense of the word, of course, is not stored in the genes. Or are we again going to venture in the hackneyed nature-nurture debate?
So yes, ancient DNA research certainly yields new insights, but you must always be cautious and compare them with findings from other sciences such as classical archeology, linguistics and sociology. In my review in my History Account on Goodreads, I highlight some of those new insights. See https://www.goodreads.com/review/show....
David Reich portrays this clearly and in great detail, and with authority, because he is one of the pioneers in this field. With his own laboratory in Cambridge, Ma., he is at the forefront of this fast-growing field of the Ancient DNA revolution. His expertise is indisputable, but it also gives this book a certain amount of technicality, making it at times a bit difficult for the layman to follow his train of thought. And as an interested party, Reich naturally stresses the great merits of ancient genetic research, and rightly so, but I want to warn against overestimation, because there are considerable limitations to this kind of research.
In the first place, it is extremely difficult to find usable DNA within fossils: DNA breaks down with time, and all the more in warm and humid areas. The consequence of this is that it is currently very difficult to extract DNA from fossils older than 100,000 years, or from areas that are tropical. Obviously this gives a bias. Reich himself admits that 90% of all fossils examined up to the end of 2017 come from western Eurasia; if that's not an imbalance, then I don't know. Perhaps this will be corrected over time (China is in the process of catching up), but still.
Moreover, the total number of fossils investigated is still relatively limited, and the techniques used are in full development. Genetics and certainly Ancient Genetics is a relatively young science, and so you can see that in this book Reich has to radically contradict findings that were published in scientific journals even as recent as 2010. This should encourage vigilance and (healthy) skepticism. On top of that, it turns out that the interpretation of genetic research is always a statistical thing, in other words genetics is a probabilistic science, and so caution is all the more necessary.
Very little of this is noticeable in this book. Reich seems to be the typical example of a scientist who mainly sees the possibilities/opportunities and who remains fundamentally optimistic about revolutionary new insights and techniques. To some extent his pride is justified, for the new discoveries certainly are impressive. But it is best for anyone reading this book to remember that Reich's presentation - however fascinating - is a preliminary state of affairs, of a new science that is constantly evolving.
Finally, there is the fundamental debate to what extent genetic material can be used to derive a complete picture of human history. Of course it cannot. Genetic material teaches us revolutionary new things about when and where human populations emerged, how they related to each other, and it also offers, in part, insight into social relationships, nutrition and diseases. But the entire world of human culture in the broadest sense of the word, of course, is not stored in the genes. Or are we again going to venture in the hackneyed nature-nurture debate?
So yes, ancient DNA research certainly yields new insights, but you must always be cautious and compare them with findings from other sciences such as classical archeology, linguistics and sociology. In my review in my History Account on Goodreads, I highlight some of those new insights. See https://www.goodreads.com/review/show....
February 14, 2021
(อ่านต้นฉบับภาษาอังกฤษ)
สนุกมาก ใครสนใจ ancient genomics วิทยาศาสตร์แขนงค่อนข้างใหม่ว่าด้วยรหัสพันธุกรรมของคนโบราณ อ่านเล่มนี้เล่มเดียวจะได้เข้าใจทั้งประวัติศาสตร์วิทยาศาสตร์แขนงนี้ ข้อค้นพบสำคัญๆ ไปจนถึงความท้าทายอย่างเช่นความอ่อนไหวทางวัฒนธรรม (เช่น ชาวอินเดียนแดงบางเผ่าในอเมริกาไม่ยอมให้เอาดีเอ็นเอของบรรพบุรุษมาวิเคราะห์)
ประเด็นที่รู้สึกว่าน่าทึ่งที่สุดในหนังสือคือข้อค้นพบที่ว่า “pure race” หรือสายพันธุ์บริสุทธิ์ไม่มีอยู่จริง เพราะมนุษย์ต่างเผ่าต่างผสมพันธุ์ข้ามสายไปมานับตั้งแต่อดีตหลายพันปีที่แล้ว แม้แต่มนุษย์ Homo sapiens ยุคแรกยังเคยผสมพันธุ์กับ Neanderthals เป็นปกติ (ผู้เขียนอธิบายเหตุผลที่สายพันธุ์นี้ค่อยๆ หายไป จากมุมการวิเคราะห์ยีนอย่างสนุกสนาน) ทั้งหมดนี้ทำให้ภาพ “ต้นไม้วิวัฒนาการ” ที่แตกแขนงมนุษย์สายพันธุ์ต่างๆ แยกขาดจากกันนั้นเป็นภาพที่ล้าสมัยไปแล้ว
ผู้เขียนซึ่งก็เป็นผู้บุกเบิกสาขา ancient genomics คนหนึ่งเล่าเรื่องอย่างสนุกสนานและเข้าใจง่าย ชอบการแยกแยะระหว่าง race (เชื้อชาติ) กับ population (ประชากร แยกโดยยีน) บทที่ว่าด้วยการผสมยีนของคนยุโรปอ่านแล้วไม่อินเท่ากับเรื่องราวของคนเอเชีย เพราะเหมือนได้อ่านเรื่องของบรรพบุรุษ :> ที่ชอบมากคือการอธิบายยีนของคนอินเดียว่าอินเดียเหนือกับใต้ต่างกันอย่างไร และการหักล้างทฤษฎีที่ว่าจักรวรรดิอังกฤษสมัยเป็นเจ้าอาณานิคมอินเดียกีดกันการผสมพันธ์ุข้ามวรรณะ
ตอนท้ายของหนังสือสรุปความท้าทายของแขนงนี้ซึ่งแน่นอนว่าจะมีดราม่าตามมาอีกมากมายในอนาคต
สนุกมาก ใครสนใจ ancient genomics วิทยาศาสตร์แขนงค่อนข้างใหม่ว่าด้วยรหัสพันธุกรรมของคนโบราณ อ่านเล่มนี้เล่มเดียวจะได้เข้าใจทั้งประวัติศาสตร์วิทยาศาสตร์แขนงนี้ ข้อค้นพบสำคัญๆ ไปจนถึงความท้าทายอย่างเช่นความอ่อนไหวทางวัฒนธรรม (เช่น ชาวอินเดียนแดงบางเผ่าในอเมริกาไม่ยอมให้เอาดีเอ็นเอของบรรพบุรุษมาวิเคราะห์)
ประเด็นที่รู้สึกว่าน่าทึ่งที่สุดในหนังสือคือข้อค้นพบที่ว่า “pure race” หรือสายพันธุ์บริสุทธิ์ไม่มีอยู่จริง เพราะมนุษย์ต่างเผ่าต่างผสมพันธุ์ข้ามสายไปมานับตั้งแต่อดีตหลายพันปีที่แล้ว แม้แต่มนุษย์ Homo sapiens ยุคแรกยังเคยผสมพันธุ์กับ Neanderthals เป็นปกติ (ผู้เขียนอธิบายเหตุผลที่สายพันธุ์นี้ค่อยๆ หายไป จากมุมการวิเคราะห์ยีนอย่างสนุกสนาน) ทั้งหมดนี้ทำให้ภาพ “ต้นไม้วิวัฒนาการ” ที่แตกแขนงมนุษย์สายพันธุ์ต่างๆ แยกขาดจากกันนั้นเป็นภาพที่ล้าสมัยไปแล้ว
ผู้เขียนซึ่งก็เป็นผู้บุกเบิกสาขา ancient genomics คนหนึ่งเล่าเรื่องอย่างสนุกสนานและเข้าใจง่าย ชอบการแยกแยะระหว่าง race (เชื้อชาติ) กับ population (ประชากร แยกโดยยีน) บทที่ว่าด้วยการผสมยีนของคนยุโรปอ่านแล้วไม่อินเท่ากับเรื่องราวของคนเอเชีย เพราะเหมือนได้อ่านเรื่องของบรรพบุรุษ :> ที่ชอบมากคือการอธิบายยีนของคนอินเดียว่าอินเดียเหนือกับใต้ต่างกันอย่างไร และการหักล้างทฤษฎีที่ว่าจักรวรรดิอังกฤษสมัยเป็นเจ้าอาณานิคมอินเดียกีดกันการผสมพันธ์ุข้ามวรรณะ
ตอนท้ายของหนังสือสรุปความท้าทายของแขนงนี้ซึ่งแน่นอนว่าจะมีดราม่าตามมาอีกมากมายในอนาคต
March 27, 2022
Overall, interesting & would have been a lot better if the editor had given him a limited space in which to make his arguments. The science got a solid 5 stars, the delivery wandered between 2 & 3 stars. I'd give this 4 stars if I was feeling generous, but he put my teeth on edge a little too often.
The Good: Well narrated & full of really interesting findings even if many are somewhat iffy due to new methods & small sets for statistical analysis. They certainly open our eyes to the complexity of our ancestors' lives, migrations, & breeding. Societies couldn't have been as static as we once thought & ancient DNA is proving that there were 'ghost populations', entire peoples that we have no anthropological evidence for yet. We might never have that evidence, but some of the story is in the gene groups they have passed down such as the genomic signatures of inequality; usually the subservient or conquered race showing signs of the male conquerors or rulers DNA but not female as shown by the Y chromosome & mitochondrial DNA.
The Bad: His explanations confused me too often. He'd state a point as part of larger statement which I might or might not get. I might be willing to just go with it, but then he'd make a convoluted explanation that completely lost me. Sometimes this was through redundancy. An example or two would be fine, but 4 or 5 would either make me lose the point or they had enough differences that I'd get confused. In several cases, he seemed to take a stance & then keep talking until it seemed as if he'd reversed course. This usually happened in politically sensitive topics where he seemed to want to please everyone.
Reich always refers to work as taking place in HIS laboratory. It irks me because even though he acknowledges working with others, he never mentions that they did most, if not all, the heavy lifting since he's clearly in a position of oversight much of the time. If he had even occasionally said "we" or "our", I would have liked it a lot better.
The Ugly - RACE: He did an excellent job handling this at first. It's touchy & one of the ugliest subjects to deal with since "race" is such a fraught word.
...On the one side there are beliefs about the nature of the differences that are grounded in bigotry and have little basis in reality. On the other side there is the idea that any biological differences among populations are so modest that as a matter of social policy they can be ignored and papered over. It is time to move on from this paralyzing false dichotomy and to figure out what the genome is actually telling us...
There is more genetic variation within 'races' (even using Feldman's 7 genetic clusters rather than the traditional 3) than between them, but that doesn't mean the overall differences aren't important in the sciences. They help doctors narrow down symptoms for conditions that are more likely to occur in some groups & forensic scientists to figure out just who died. I like that he also pointed out that as the speed & accuracy of genetic testing increases, such categories will become less important, especially in medicine. They'll have to since we're mixing more.
All good to that point, but then he blathered on & lost me. He really should have stopped trying to explain in many instances. In this, it was similar to A Troublesome Inheritance: Genes, Race and Human History which is both instructive & amusing since Reich takes Wade to task for making assertions that I remember as possibilities, not fact. This is something which Reich also stresses. In my review of Wade's book, I wrote, "If he had stuck to these points, the book would have been a lot shorter & I would have liked it better. Instead he tries very hard to appease the politically correct, so he broadens his examples into areas that I thought were sketchy." That applies to this book as well. OK, the amusement is minor, but it is instructive that both think Political Correctness is damaging this area of research & they provided quite a few examples including their own efforts to avoid getting on the wrong side of it. I found Reich's wiggling & over explaining even more annoying than Wade's.
We really need a set of new words to describe groupings of people that don't trigger everyone, a point he passes over quickly without offering any solutions. That might have been the biggest disappointment by the end of the book since he's in the position to provide them.
Table of Contents
Introduction
Part I The Deep History of Our Species
- 1 How the Genome Explains Who We Are
- 2 Encounters with Neanderthals
- 3 Ancient DNA Opens the Floodgates
Part II How We Got to Where We Are Today
- 4 Humanity’s Ghosts
- 5 The Making of Modern Europe
- 6 The Collision That Formed India
- 7 In Search of Native American Ancestors
- 8 The Genomic Origins of East Asians
- 9 Rejoining Africa to the Human Story
Part III The Disruptive Genome
- 10 The Genomics of Inequality
- 11 The Genomics of Race and Identity
- 12 The Future of Ancient DNA
The Good: Well narrated & full of really interesting findings even if many are somewhat iffy due to new methods & small sets for statistical analysis. They certainly open our eyes to the complexity of our ancestors' lives, migrations, & breeding. Societies couldn't have been as static as we once thought & ancient DNA is proving that there were 'ghost populations', entire peoples that we have no anthropological evidence for yet. We might never have that evidence, but some of the story is in the gene groups they have passed down such as the genomic signatures of inequality; usually the subservient or conquered race showing signs of the male conquerors or rulers DNA but not female as shown by the Y chromosome & mitochondrial DNA.
The Bad: His explanations confused me too often. He'd state a point as part of larger statement which I might or might not get. I might be willing to just go with it, but then he'd make a convoluted explanation that completely lost me. Sometimes this was through redundancy. An example or two would be fine, but 4 or 5 would either make me lose the point or they had enough differences that I'd get confused. In several cases, he seemed to take a stance & then keep talking until it seemed as if he'd reversed course. This usually happened in politically sensitive topics where he seemed to want to please everyone.
Reich always refers to work as taking place in HIS laboratory. It irks me because even though he acknowledges working with others, he never mentions that they did most, if not all, the heavy lifting since he's clearly in a position of oversight much of the time. If he had even occasionally said "we" or "our", I would have liked it a lot better.
The Ugly - RACE: He did an excellent job handling this at first. It's touchy & one of the ugliest subjects to deal with since "race" is such a fraught word.
...On the one side there are beliefs about the nature of the differences that are grounded in bigotry and have little basis in reality. On the other side there is the idea that any biological differences among populations are so modest that as a matter of social policy they can be ignored and papered over. It is time to move on from this paralyzing false dichotomy and to figure out what the genome is actually telling us...
There is more genetic variation within 'races' (even using Feldman's 7 genetic clusters rather than the traditional 3) than between them, but that doesn't mean the overall differences aren't important in the sciences. They help doctors narrow down symptoms for conditions that are more likely to occur in some groups & forensic scientists to figure out just who died. I like that he also pointed out that as the speed & accuracy of genetic testing increases, such categories will become less important, especially in medicine. They'll have to since we're mixing more.
All good to that point, but then he blathered on & lost me. He really should have stopped trying to explain in many instances. In this, it was similar to A Troublesome Inheritance: Genes, Race and Human History which is both instructive & amusing since Reich takes Wade to task for making assertions that I remember as possibilities, not fact. This is something which Reich also stresses. In my review of Wade's book, I wrote, "If he had stuck to these points, the book would have been a lot shorter & I would have liked it better. Instead he tries very hard to appease the politically correct, so he broadens his examples into areas that I thought were sketchy." That applies to this book as well. OK, the amusement is minor, but it is instructive that both think Political Correctness is damaging this area of research & they provided quite a few examples including their own efforts to avoid getting on the wrong side of it. I found Reich's wiggling & over explaining even more annoying than Wade's.
We really need a set of new words to describe groupings of people that don't trigger everyone, a point he passes over quickly without offering any solutions. That might have been the biggest disappointment by the end of the book since he's in the position to provide them.
Table of Contents
Introduction
Part I The Deep History of Our Species
- 1 How the Genome Explains Who We Are
- 2 Encounters with Neanderthals
- 3 Ancient DNA Opens the Floodgates
Part II How We Got to Where We Are Today
- 4 Humanity’s Ghosts
- 5 The Making of Modern Europe
- 6 The Collision That Formed India
- 7 In Search of Native American Ancestors
- 8 The Genomic Origins of East Asians
- 9 Rejoining Africa to the Human Story
Part III The Disruptive Genome
- 10 The Genomics of Inequality
- 11 The Genomics of Race and Identity
- 12 The Future of Ancient DNA
April 14, 2018
This was a fantastic condensation of modern research on genomics and it's effect on our understanding of anthropology and history. Really, what is it with biologists that they are able to write these books understandable to a relatively lay audience without hiding entire detail about how the scientists go about doing their research and draw conclusions:
Not that some details are hidden. Like use of Principal Component Analysis and other statistical techniques and how they get around problems with these techniques is mostly elided. Still it was fun learning about things Four Population Tests to identify likely common ancestors and how they group current and past populations of people.
The weakest parts of the book are when Reich is trying to walk the tight rope of modern connections between race, behavior and genetics. Which is understandable, because it is a difficult topic. But his bad arguments don't do well for the values he wants to espouse. There is a lot of is vs. ought confusion, with no consistency. This is especially egregious in Chapter 11. Why do I need to be reminded of treating individuals as individuals, just because we find something about group averages. There's something to be said about Nietzsche, that he was correct to claim that trying to derive all our values from objective truth is not ideal, to say the least. But an interesting quote:
Anyway the book is a lot of fun. One of the funniest parts was about them finding proof for West Eurasian ancestry of large parts of South Asian population:
So to get around this:
And for the rest of the chapter, he deadpan goes on using the ANI-ASI terminology.
Finally, no one comes out looking good when you go far back in time. And we are mixes all the way down.
We scientists are conditioned by the system of research funding to justify what we do in terms of practical application to health or technology. But shouldn’t intrinsic curiosity be valued for itself? Shouldn’t fundamental inquiry into who we are be the pinnacle of what we as a species hope to achieve? Isn’t an attribute of an enlightened society that it values intellectual activity that may not have immediate economic or other practical impact? The study of the human past—as of art, music, literature, or cosmology—is vital because it makes us aware of aspects of our common condition that are profoundly important and that we heretofore never imagined.
Not that some details are hidden. Like use of Principal Component Analysis and other statistical techniques and how they get around problems with these techniques is mostly elided. Still it was fun learning about things Four Population Tests to identify likely common ancestors and how they group current and past populations of people.
The weakest parts of the book are when Reich is trying to walk the tight rope of modern connections between race, behavior and genetics. Which is understandable, because it is a difficult topic. But his bad arguments don't do well for the values he wants to espouse. There is a lot of is vs. ought confusion, with no consistency. This is especially egregious in Chapter 11. Why do I need to be reminded of treating individuals as individuals, just because we find something about group averages. There's something to be said about Nietzsche, that he was correct to claim that trying to derive all our values from objective truth is not ideal, to say the least. But an interesting quote:
I have deep sympathy for the concern that genetic discoveries about differences among populations may be misused to justify racism. But it is precisely because of this sympathy that I am worried that people who deny the possibility of substantial biological differences among populations across a range of traits are digging themselves into an indefensible position, one that will not survive the onslaught of science. In the last couple of decades, most population geneticists have sought to avoid contradicting the orthodoxy. When asked about the possibility of biological differences among human populations, we have tended to obfuscate, making mathematical statements in the spirit of Richard Lewontin about the average difference between individuals from within any one population being around six times greater than the average difference between populations. We point out that the mutations that underlie some traits that differ dramatically across populations—the classic example is skin color—are unusual, and that when we look across the genome it is clear that the typical differences in frequencies of mutations across populations are far less. But this carefully worded formulation is deliberately masking the possibility of substantial average differences in biological traits across populations.
Anyway the book is a lot of fun. One of the funniest parts was about them finding proof for West Eurasian ancestry of large parts of South Asian population:
They did not want to be part of a study that suggested a major West Eurasian incursion into India without being absolutely certain as to how the whole-genome data could be reconciled with their mitochondrial DNA findings. They also implied that the suggestion of a migration from West Eurasia would be politically explosive. They did not explicitly say this, but it had obvious overtones of the idea that migration from outside India had a transformative effect on the subcontinent.
So to get around this:
We wrote that the people of India today are the outcome of mixtures between two highly differentiated populations, “Ancestral North Indians” (ANI) and “Ancestral South Indians” (ASI), who before their mixture were as different from each other as Europeans and East Asians are today. The ANI are related to Europeans, central Asians, Near Easterners, and people of the Caucasus, but we made no claim about the location of their homeland or any migrations. The ASI descend from a population not related to any present-day populations outside India. We showed that the ANI and ASI had mixed dramatically in India. The result is that everyone in mainland India today is a mix, albeit in different proportions, of ancestry related to West Eurasians, and ancestry more closely related to diverse East Asian and South Asian populations. No group in India can claim genetic purity.
And for the rest of the chapter, he deadpan goes on using the ANI-ASI terminology.
Finally, no one comes out looking good when you go far back in time. And we are mixes all the way down.
January 30, 2019
|| Who We Are And How We Got Here: Ancient DNA and the New Science of the Human Past by David Reich ||
Reich does an admirable job laying out the field of genomics and its implications on our understanding of human origins, migration patterns, and related fields of linguistics, and medicine.
The book pulls largely from Reich's own research work and samples at his Harvard laboratory. He navigates the ethics of genetic research with special sensitivity to how this research has been abused and misused in the past, leading to oppression, genocide, and decades of struggle for many people groups throughout history.
While any book claiming to have the "new" research will be inevitably superceded, this is the book to check out right now for a 2010s-landscape view of genetics, and population studies.
Completely fascinating.
Reich does an admirable job laying out the field of genomics and its implications on our understanding of human origins, migration patterns, and related fields of linguistics, and medicine.
The book pulls largely from Reich's own research work and samples at his Harvard laboratory. He navigates the ethics of genetic research with special sensitivity to how this research has been abused and misused in the past, leading to oppression, genocide, and decades of struggle for many people groups throughout history.
While any book claiming to have the "new" research will be inevitably superceded, this is the book to check out right now for a 2010s-landscape view of genetics, and population studies.
Completely fascinating.
May 21, 2021
«Хто ми такі? Походження людини крізь призму ДНК»
⠀
Девід Райх, «Наш Формат», 2019
⠀
«Who We Are and How We Got Here. Ancient DNA and the New Science of the Human Past»
⠀
David Reigh, 2018
⠀
«Рух - це життя!»
⠀
І цей вислів має реальне підґрунтя для людства. Вся історія людської популяції - це рух, переселення і схрещування.
⠀
Чи таке цільне поняття раси й національності?
⠀
Чи вірні наші уявлення про минуле людства?
⠀
Чи знаєте ви насправді, хто були ваші предки?
⠀
Наука стрімко розвивається, методи досліджень постійно змінюються, археологи співпрацюють з генетиками та антропологами, щоб відкрити завісу на історію нашого виду.
⠀
Зараз легко замовити тест своєї ДНК, щоб дізнатися звідки ви отримали такий «коктейль» генів і мутацій, та чи він на 100% вірний?
⠀
Ця книжка не читається легко, але вона цікаво й доступно розповідає про важливі відкриття в генетиці й питані походження людини.
⠀
Раджу до прочитання тим, хто любить історію й археологію, та хоч раз задумався про тест ДНК!
⠀
Про книжку:
⠀
«ПРО КНИЖКУ
⠀
Історія науки показує, як небезпечно бути переконаним у тому, що знаєш істину. Усі помилки — починаючи від уявлення, що Земля пласка, а Сонце обертається навколо неї — мають стати для нас попередженням і навчити піддавати сумнівам інформацію та не довіряти стереотипам. Генетик Девід Райх переконаний: геномна революція стрімко ламає наші уявлення про минуле. Чим ми відрізняємось одне від одного? Що таке ідентичність? У своїй книжці дослідник описує сучасні відкриття, пов’язані з вивченням і порівнянням стародавньої та сучасної ДНК.
⠀
ДЛЯ КОГО КНИЖКА
⠀
Книжка для всіх, хто любить науково-популярну літературу, цікавиться науковими дослідженнями у сфері генетики та минулим людства.
⠀
ЧОМУ ЦЯ КНИЖКА
⠀
Автор показує зміни, які відбувалися з популяціями людей у далекому минулому, доводячи, що ДНК може розповісти про історію людства значно більше, ніж традиційний арсенал археології.
⠀
ПРО АВТОРА
⠀
Девід Райх — професор генетики в Гарвардській медичній школі й один з провідних фахівців, що займаються аналізом ДНК стародавніх людей. У 2015 році журнал Nature зарахував його до десяти найвидатніших учених за внесок у науку.»
⠀
#примхливачитака
⠀
Девід Райх, «Наш Формат», 2019
⠀
«Who We Are and How We Got Here. Ancient DNA and the New Science of the Human Past»
⠀
David Reigh, 2018
⠀
«Рух - це життя!»
⠀
І цей вислів має реальне підґрунтя для людства. Вся історія людської популяції - це рух, переселення і схрещування.
⠀
Чи таке цільне поняття раси й національності?
⠀
Чи вірні наші уявлення про минуле людства?
⠀
Чи знаєте ви насправді, хто були ваші предки?
⠀
Наука стрімко розвивається, методи досліджень постійно змінюються, археологи співпрацюють з генетиками та антропологами, щоб відкрити завісу на історію нашого виду.
⠀
Зараз легко замовити тест своєї ДНК, щоб дізнатися звідки ви отримали такий «коктейль» генів і мутацій, та чи він на 100% вірний?
⠀
Ця книжка не читається легко, але вона цікаво й доступно розповідає про важливі відкриття в генетиці й питані походження людини.
⠀
Раджу до прочитання тим, хто любить історію й археологію, та хоч раз задумався про тест ДНК!
⠀
Про книжку:
⠀
«ПРО КНИЖКУ
⠀
Історія науки показує, як небезпечно бути переконаним у тому, що знаєш істину. Усі помилки — починаючи від уявлення, що Земля пласка, а Сонце обертається навколо неї — мають стати для нас попередженням і навчити піддавати сумнівам інформацію та не довіряти стереотипам. Генетик Девід Райх переконаний: геномна революція стрімко ламає наші уявлення про минуле. Чим ми відрізняємось одне від одного? Що таке ідентичність? У своїй книжці дослідник описує сучасні відкриття, пов’язані з вивченням і порівнянням стародавньої та сучасної ДНК.
⠀
ДЛЯ КОГО КНИЖКА
⠀
Книжка для всіх, хто любить науково-популярну літературу, цікавиться науковими дослідженнями у сфері генетики та минулим людства.
⠀
ЧОМУ ЦЯ КНИЖКА
⠀
Автор показує зміни, які відбувалися з популяціями людей у далекому минулому, доводячи, що ДНК може розповісти про історію людства значно більше, ніж традиційний арсенал археології.
⠀
ПРО АВТОРА
⠀
Девід Райх — професор генетики в Гарвардській медичній школі й один з провідних фахівців, що займаються аналізом ДНК стародавніх людей. У 2015 році журнал Nature зарахував його до десяти найвидатніших учених за внесок у науку.»
⠀
#примхливачитака
April 26, 2022
Improved methods to extract DNA from the bones of ancient humans who lived tens of thousands of years ago has allowed geneticists to complement the work of archaeologists and linguists in reconstructing past human migrations. Reich provides readers with a ‘primer’ on genetics and DNA sequencing before reconstructing the histories of modern Europeans, Indians, Native Americans, East Asians and Africans.
First of all, Reich points out that the Neanderthals, who lived in Europe for thousands of years before modern Homo sapiens arrived around 44,000 years ago. While Neanderthals eventually became extinct, all modern humans outside Africa, still carry about 2 percent of Neanderthal genes. The question is why did our ancestors replace the Neanderthals?
Ancient hunter-gatherers of Europe intermingled with farmers from Anatolia (modern Turkey) about 9,000 years ago, followed by an influx of herders from the Asian steppes. It turns out that these herders’ genes make up about half the genes of Northern Europeans beginning about 5,000 years ago. How did this group supplant the farmer populations?
The DNA samples suggest that the steppe peoples acquired plague, developed some immunity with exposure, and then transmitted it to unexposed European farmers—much like Europeans decimated Native American populations through diseases like small pox. [Roughly 7 percent of ancient DNA samples from Europe and the steppes contain DNA of the plague microbe that caused medieval Europe’s Black Death.]
The main learning that Reich explains is that human populations ebb and flow over time through various migratory behaviors. For instance, most people of European descent have close genetic and linguistic ties with near eastern and north Indian people. This stems from migrations around 5,000 years ago from the vast Steppe, the grass plains near the Black and Caspian seas.
Fascinating account of population history and supports why all of us are a blend of DNA from multiple sources.
First of all, Reich points out that the Neanderthals, who lived in Europe for thousands of years before modern Homo sapiens arrived around 44,000 years ago. While Neanderthals eventually became extinct, all modern humans outside Africa, still carry about 2 percent of Neanderthal genes. The question is why did our ancestors replace the Neanderthals?
Ancient hunter-gatherers of Europe intermingled with farmers from Anatolia (modern Turkey) about 9,000 years ago, followed by an influx of herders from the Asian steppes. It turns out that these herders’ genes make up about half the genes of Northern Europeans beginning about 5,000 years ago. How did this group supplant the farmer populations?
The DNA samples suggest that the steppe peoples acquired plague, developed some immunity with exposure, and then transmitted it to unexposed European farmers—much like Europeans decimated Native American populations through diseases like small pox. [Roughly 7 percent of ancient DNA samples from Europe and the steppes contain DNA of the plague microbe that caused medieval Europe’s Black Death.]
The main learning that Reich explains is that human populations ebb and flow over time through various migratory behaviors. For instance, most people of European descent have close genetic and linguistic ties with near eastern and north Indian people. This stems from migrations around 5,000 years ago from the vast Steppe, the grass plains near the Black and Caspian seas.
Fascinating account of population history and supports why all of us are a blend of DNA from multiple sources.
December 30, 2018
Due to Goodreads limits, this review is cropped. The full review can be found at http://bahanonu.com/syscarut/articles/204/.
=======
DNA vs Archeology
Estimating the past from genomic data.
[image error]
Good illustration of why whole genome analysis can be very useful.
Example of principal component analysis to reduce many genetic variations across groups into a single, easy to read graph.
[image error]
Text has many simple illustrations that help get scientific points across.
[image error]
Different statistics for admixture from Schaefer, 2016. Reich could have included a paragraph or two on comparison between methods.
=======
Full review: http://bahanonu.com/syscarut/articles/204/.
=======
This review will likely be updated as I mull over or re-read the book.
[…] when we discover biological differences governing behavior, they may not be working in the way we naively assume. — David Reich, Who We Are and How We Got Here.
Reich has done a tremendous job condensing the work of many people and disparate areas of research into a compelling story that is potentially more informative for the history and process behind the scientific discoveries than the conclusions or his commentary on their societal effects. While the book is highly recommended based alone on the wealth of new ideas and potential to upturn old facts accepted by many, and is the reason I gave it a high rating rather than because I agree with everything said, it should be read with caution and an eye for "what is not said" for reasons pointed out below.
DNA vs Archeology
The book is mainly divided into an introductory portion, where the story of the Neanderthals helps provide a basis to go over techniques used in the ancient DNA field. Reich then moves across the globe—from Europe through India, the Americas, East Asians, and Africa—and goes over different migratory patterns that have been revealed by ancient DNA analysis. In addition, as is the case with India, he shows cases where endogamy (marrying within certain groups) can be demonstrated by analysis of highly unlikely similarity of DNA coding regions across time in specific populations. Further, he also shows how cases like the "Star Cluster" can help demonstrate cases in which specific males (or groups of males) had an outsized levels of breeding success, potentially due to war or migration as mentioned previously. An interesting question that he does not really address is the use of ancient DNA analysis to show how monogamy or polygamy play out in actuality, or if there was more cheating going on than would be expected giving stated societal norms across time and regions. Lastly, he ends looking both at the future (good) and the ethical implications of ancient DNA analysis (the weakest part of the book, more on that later). Overall, the style suites the topic really well and is a great way to get people new to the field acquainted with a forest-level view.
Reich does a convincing job of showing the advantages of ancient DNA analysis over traditional archeology in certain areas, such as pointing out the discrepancy between archeologists claiming that for there to have been a large incursion of non-Indians into that subcontinent, replacing people and leaving a genetic footprint, that there would be carbon, etc. evidence of burnt towns, etc. But the well recorded fall of Rome by the Visigoths and others did not leave such a record to the degree anticipated, throwing such conclusions into doubt. This can be captured in the classic phrase "absence of evidence is not the evidence of absence".
Estimating the past from genomic data.
However, and this is a theme about my criticisms of the book, he does not provide examples or speculate on places where the archeological record does show migration or invasion but there is not much ancient or modern DNA evidence left. Two scenarios (of many) would be an invasion where the invading population did not breed much with the locals despite large changes to civilization (think modern American wars) or pass through migrations on the way to some other destination (if those occurred). It would have been informative for him to spend time on the limits of what could possibly be known given ancient DNA basically relies on the dynamics of sex to have occurred in some predicted pattern (e.g. conquering males impregnating conquered females). Further, it is not clear how much the Star Cluster or similar traits is due to a single male or many closely related males, e.g. whether there is a limitation in what this type of analysis can tell us. These might be hidden within academic reviews, but the point of this book should be to give a high-level view of the pros and cons of ancient DNA analysis without a reader needing to get their hands dirty on the first pass.
[image error]
Good illustration of why whole genome analysis can be very useful.
On the other hand, he does a good job pointing out several neat ideas, such as due to the random splitting of DNA during production of gametes, that several generations back one is unlikely to contain DNA from all ones ancestors (by sexual reproduction). In addition, he does a good job at attacking old dogmas that are based on bad assumptions, such as Richard Lewontin's 1972 study The Apportionment of Human Diversity (see Lewontin's Fallacy, that don't take into account the whole genome or correlations between variations across the genome. This type of thinking is still prevalent, as can be seen in a recent National Geographic issue, see There’s No Scientific Basis for Race—It's a Made-Up Label.
In addition, his small aside about finding that the cochlear contains the best store of ancient DNA is fun and could potentially have been an opportunity to point out serendipity in science (should that be the case here). There are several other times, such as the story of discovering "ghost" populations that may no longer exists but related Europeans and Native Americans that was resolved finding the Mal'ta boy, where he brings up cool stories of how science leads to hypotheses turns to field work and final novel insights about the world. This is captured in a nice assertion Reich makes near the beginning:
We scientists are conditioned by the system of research funding to justify what we do in terms of practical application to health or technology. But shouldn’t intrinsic curiosity be valued for itself? Shouldn’t fundamental inquiry into who we are be the pinnacle of what we as a species hope to achieve? Isn’t an attribute of an enlightened society that it values intellectual activity that may not have immediate economic or other practical impact? The study of the human past—as of art, music, literature, or cosmology—is vital because it makes us aware of aspects of our common condition that are profoundly important and that we heretofore never imagined. — David Reich, Who We Are and How We Got Here.
And it reminds me of Richard Feynman's excellent The Value of Science essay and a key quote:
Another value of science is the fun called intellectual enjoyment which some people get from reading and learning and thinking about it, and which others get from working in it. This is an important point, one which is not considered enough by those who tell us it is our social responsibility to reflect on the impact of science on society. — Richard Feynman The Value of Science.
Reich also gives overviews of several techniques used in the field to identify likely common ancestors (Four Population Test) and to group current and past groups of people (e.g. principal component analysis). These are supplemented by excellent diagrams. However, he doesn't spend much time pointing out to the reader problems with these techniques or how they get around them. This is especially important as it relates to discussions of grouping people into categories based on (in the book) obvious delineations between say Europeans and some Asians subcategories.
Our initial approach was to carry out a principal component analysis, which can identify combinations of mutation frequencies that are most efficient at finding differences among samples. — David Reich, Who We Are and How We Got Here.
Example of principal component analysis to reduce many genetic variations across groups into a single, easy to read graph.
As a scientist, and knowing how quickly new fields can evolve and old methods be found to contain technical and conceptual errors, I am alarmed by Reich's lack of giving any kind of confidence (mathematical or otherwise) about statements being made that upturn old archeological or other theories. Given many studies he cited are less than a decade, sometimes only a couple years old, this is concerning. He does not spend much time going over more caveats to the technical methods (e.g. extraction of DNA from ancient samples, though he does talk about some initial challenges and solutions in the case of Neanderthal DNA) or conceptual ideas (e.g. Four Population Test). This is evidenced, for example, in his out of place bringing up of the Jefferson-Hemings relationship that adds nothing to the story but he presents as if it has been conclusively shown (with genetics, while glossing over the caveats). More humility about the possibilities of ancient DNA analysis would have strengthened the book.
[image error]
Text has many simple illustrations that help get scientific points across.
Reich would also have done well to specifically state who he is referring to when he makes comments about those wanting to return to a 'racially pure' state, while he leaves their timescale for determining purity indefinite. Those discussing maintaining a recent European stock in their writings (e.g. The Daily Stormer, American Renaissance, Occidental Dissent, etc.) are slightly different that those proposing old Nordic Theories and similar stories (e.g. see The Long Journey, The Rising Tide of Color: Against White World Supremacy, etc.). He does briefly mention the Eurogenes and several other blogs, but only in passing and not directly in relation to his reference to 'racists' and 'bigots'. Further, he then contradicts himself by pointing out:
However, in Europe, where we have made most progress in the ancient DNA revolution so far, we know that by four thousand years ago, many populations were already highly similar in their ancestry composition to those of today. […] For example, the classic measure of genetic differentiation between two British populations is about one hundred times smaller than the same measurement of population differentiation comparing Europeans to East Asians. — David Reich, Who We Are and How We Got Here.
That he does not attempt to reconcile these comments about populations that are relatively homogenous and have not mixed much over recent history leaves room for people to misinterpret or use such findings to justify their beliefs.
Ancient DNA has established major migration and mixture between highly divergent populations as a key force shaping human prehistory, and ideologies that seek a return to a mythical purity are flying in the face of hard science. — David Reich, Who We Are and How We Got Here.
In addition, at the end of several chapters and throughout the book Reich makes reference to 'racial purity' not being a thing—without taking care to note that purity depends on the timescale used and, thus, is an annoying strawman. As noted above, he also contradicts this statement in several cases, among which include the distinct ethnic groups in Indian that have been maintained for tens of generations even among physically mixed populations.
Around a third of Indian groups experienced population bottlenecks as strong or stronger than the ones that occurred among Finns or Ashkenazi Jews. […]Many of the population bottlenecks in India were also exceedingly old. […] It meant that after the population bottleneck, the ancestors of the Vysya had maintained strict endogamy, allowing essentially no genetic mixing into their group for thousands of years. Even an average rate of influx into the Vysya of as little as 1 percent per generation would have erased the genetic signal of a population bottleneck. The ancestors of the Vysya did not live in geographic isolation.[…] And the Vysya were not unique. A third of the groups we analyzed gave similar signals, implying thousands of groups in India like this. — David Reich, Who We Are and How We Got Here.
In addition, he also seems focused on the idea of human migrations to the exclusion of focusing on how ancient DNA can tell us about changes occurring in non-migratory populations (thought he hints at the end of the book about this). For example, this could address Clark's A Farewell to Alms assertion about rich Britons breeding more being a reason for the industrial revolution and would be a starting point for many interesting analyses. During the discussion of the low occurrence of mixture between physically inter-mixed groups within India, e.g. endogamy or the caste system, he then goes on a tangent about his Jewishness and how he sympathized with the (unnamed) people who were prevent from finding love outside their ethnic/social group. These very overt tendencies to favor mixture over non-mixture are concerning in that he doesn't state in reality what guides his (and those in the fields) scientific questions and how that might bias future hypotheses or research, impacting interpretation of the past and having consequences for how society at large interprets the fields results.
The genome revolution provides us with a shared history that, if we pay proper attention, should give us an alternative to the evils of racism and nationalism, and make us realize that we are all entitled equally to our human heritage. [emphasis mine] — David Reich, Who We Are and How We Got Here.
This book, along with the excellent The Neuroscience of Intelligence by Richard Haier and many others will start to raise questions that need to be addressed by scientists and non-scientists. To put it bluntly, old and new research points toward the ability to quantify intelligence (broadly defined or by IQ) and DNA (and other) analysis has shown fairly definitively that there are different clusters of humans (e.g. ethnicities and ancestral groups for those wanting to avoid the loaded 'race' category). The question remains that once people combine the two areas of research, as China is attempting to do specifically looking at the genetics of g, are we as a society equipped to handle the results regardless of what they might be (especially if differences appear)? Will nationalism of the kind focused on celebrating a shared culture be instead directed toward war-like nationalism focused on extermination of those with traits that are not desired (by some group)? His blanket negative statements on anything tribal related—be that racism, nationalism, endogamy, etc.—cloud useful insights and suggestions that could be gleaned by a more nuanced position.
[image error]
Different statistics for admixture from Schaefer, 2016. Reich could have included a paragraph or two on comparison between methods.
In an individualistic society, ethnic history reminds us of the enduring consequences of centuries-old cultural patterns into which each individual is born. […] It is not personal merit but simply good fortune to be born into a group whose values and skills make life easier to cope with.[…]Substantial reshuffling of the rankings of nations and races at different stages of history undermine genetic explanations in general. A reshuffling of the IQ rankings of American ethnic groups within a period of half a century26 undermines the theory of genetic determination of intelligence, even aside from questions about the tests themselves. The fact that black orphans raised by white families have IQs at or above the national average27 is even stronger evidence against that theory. — Thomas Sowell, Ethnic America.
Thomas Sowell in Ethnic America appears to attribute many of the differences between ethnic groups to differences in culture and notes that persistent disparities between African-Americans/Hispanics and Caucasian-descent/Asians need to be explained. In his famous How Much Can We Boost IQ and Scholastic Achievement? and subsequent essays and books, Arthur Jensen proposes that IQ is heritable. The Bell Curve, Levin's thought-provoking Why Race Matters, and many others point toward potential genetic differences between groups. Reich somewhat addresses this field of research but does so haphazardly and at times commits the same errors as he accuses other of, e.g. when criticizing Watson and others, he notes that there is no genetic evidence of different IQ of (sub-Saharan) Africans, ignoring the evidence that there is a lower IQ (but that we don't yet know the genetic origin). He offers the following solution to deal with the fallout of finding differences between human groups:
The right way to deal with the inevitable discovery of substantial differences across populations is to realize that their existence should not affect the way we conduct ourselves. As a society we should commit to according everyone equal rights despite the differences that exist among individuals. If we aspire to treat all individuals with respect regardless of the extraordinary differences that exist among individuals within a population, it should not be so much more of an effort to accommodate the smaller but still significant average differences across populations. — David Reich, Who We Are and How We Got Here.
Given human nature toward tribalism and noticing differences, this is a naïve solution. It would have been nice for him to at least briefly note how this type of thinking jives with how humans behave in the real, non-utopian world. Seeing as he makes mention of the misuse of archeology in the past by National Socialists and others, this is not too much to ask. There are many other gaps along these lines that he should have addressed, but instead danced around or ignored.
=======
Full review: http://bahanonu.com/syscarut/articles/204/.
November 26, 2018
Not so long ago, Mayan script could not be read. It was not really until the 1970's that enough was understood to learn many of the most significant facts about the Mayan history, pre-European contact. Prior to that time, there were prominent researchers who thought that the ancient Mayan civilization was a peaceful one. Some even thought that the apparent ruined cities were actually just religious centers, which the Mayans would go to only occasionally, for ceremonies. Once the Mayan script was readable, it became apparent that the Mayan civilization was actually a lot more like ancient Greece or Renaissance Italy, with multiple warring city-states that would engage in a nearly endless series of alliances, wars, and betrayals. The archaeology could help inform this history, but it couldn't provide it in the first place; you needed to be able to read the script.
So it is with the study of prehistoric times, but the script in question is not one invented by humans, but rather one that invented humans: DNA. Archaeologists, linguists, biologists, and others have all provided valuable information about what our human, or proto-human, ancestors did or didn't do in the past. But, until recently, we couldn't actually read the DNA of the mummies, frozen corpses, or bog sacrifices which came to light from time to time. David Reich is one of the first generation of researchers who can. Hold on to your hat, we are in for a whirlwind of change and an avalanche of new findings.
My personal favorite: it appears that the blond, blue-eyed, pale-skinned northern European is not a "pure" race, Aryan or anything else, but rather the result of a mixture of three races. One, was brown skinned and brown eyed, but with blond hair. One, was brown skinned and black haired, but with blue eyes. The third, was brown eyed and black haired, with pale skin.
Reich successfully covers a heck of a lot of ground, here, in a readable and even enjoyable way. Neanderthals (and other homo-but-not-sapien species), the Indian subcontinent and castes, the origins of the Indo-Europeans, how many groups came across the Bering Strait to become the ancestors of the Native Americans, the many leavings (and occasional returns) of humans to sub-Saharan Africa (and what was happening with the people who stayed there), the settling of east Asia, and a whole host of ethical and political issues.
An example: if you get people to voluntarily donate their DNA, for the explicit purpose of using it in scientific research, taking care to get informed consent forms signed, and then their tribe announces that they do not give consent for anyone in their tribe to take part in such research, what do you do? Ignore the issue of tribal-level consent, or deny the individuals the same right to self-determination (on having their DNA sequenced) that you would give any white person? These donors took the time to donate a DNA sample and fill out the paperwork, after all, with the expectation that it would advance science; telling them it won't be used after all is sort of breaking your promise. There are no easy answers here, and there's a lot of icky history with regard to the science of genetics, and the field of research into Native American tribe's ancestors. Reich does a good job of discussing the issues in a thoughtful way.
In fact, that kind of encapsulates a lot of the issues with DNA research. We like to think of ourselves as individuals, with the right to know ourselves, but anyone who has looked into the issue of how DNA testing interacts with adoption, or infidelity, or genetic susceptibility to disease, encounters the fact that allowing one person to get the data, denies anyone related (or theoretically related) to them the option of not doing that, or keeping it private if they do. We share DNA. It ties us, and our histories and our decisions, together, even when we would rather it did not. Knowing something about your DNA, tells you something about mine as well. Not being allowed to know about your ancestors, denies me the ability to know something about mine (because we're all related, eventually). As the evidence so far shows, we have been splitting into different races, and then mixing again, for a long long time, and it has happened on every continent, multiple times.
There is also a great deal of discussion about the different things we learn from mitochondrial DNA (inherited from the mother only), Y chromosomes (inherited from the father only), and the rest of our DNA. Looking at all three types of data can tell us things we don't always like to hear about. Like, for example, tales of all of the men in a region being exterminated by the invaders, but the women appear to have survived and reproduced. It is hard to believe that most of that did not resemble ancient tales of rape and pillage. We are, all of us, descended from people who did some very bad things.
Oh, and for you "Highlander" fans, you will be happy to know that the Kurgan people are, in fact, probably the ones who spread the Indo-European languages across two continents.
I also want to point out that Reich makes excellent use of visuals to tell a complex story (or more than one). Maps,, timelines, and all manner of diagrams help us to follow the multiple splitting and merging events, and when and where they happened.
Reich admits early on that much of what he has to tell us, could be modified by more discoveries in the near future, but what we know already is enough to think on for many days. On the whole, though, what we have gotten from this new science so far, is a glimpse into a distant past, well before written history, that was as full of drama and tragedy, adventure and violence and sex as any opera or ancient Greek epic. It was all forgotten, entirely 100% forgotten and lost, for millennia. Until now. Now, like the skeleton in the closet of the human family's old house, it is all coming out.
So it is with the study of prehistoric times, but the script in question is not one invented by humans, but rather one that invented humans: DNA. Archaeologists, linguists, biologists, and others have all provided valuable information about what our human, or proto-human, ancestors did or didn't do in the past. But, until recently, we couldn't actually read the DNA of the mummies, frozen corpses, or bog sacrifices which came to light from time to time. David Reich is one of the first generation of researchers who can. Hold on to your hat, we are in for a whirlwind of change and an avalanche of new findings.
My personal favorite: it appears that the blond, blue-eyed, pale-skinned northern European is not a "pure" race, Aryan or anything else, but rather the result of a mixture of three races. One, was brown skinned and brown eyed, but with blond hair. One, was brown skinned and black haired, but with blue eyes. The third, was brown eyed and black haired, with pale skin.
Reich successfully covers a heck of a lot of ground, here, in a readable and even enjoyable way. Neanderthals (and other homo-but-not-sapien species), the Indian subcontinent and castes, the origins of the Indo-Europeans, how many groups came across the Bering Strait to become the ancestors of the Native Americans, the many leavings (and occasional returns) of humans to sub-Saharan Africa (and what was happening with the people who stayed there), the settling of east Asia, and a whole host of ethical and political issues.
An example: if you get people to voluntarily donate their DNA, for the explicit purpose of using it in scientific research, taking care to get informed consent forms signed, and then their tribe announces that they do not give consent for anyone in their tribe to take part in such research, what do you do? Ignore the issue of tribal-level consent, or deny the individuals the same right to self-determination (on having their DNA sequenced) that you would give any white person? These donors took the time to donate a DNA sample and fill out the paperwork, after all, with the expectation that it would advance science; telling them it won't be used after all is sort of breaking your promise. There are no easy answers here, and there's a lot of icky history with regard to the science of genetics, and the field of research into Native American tribe's ancestors. Reich does a good job of discussing the issues in a thoughtful way.
In fact, that kind of encapsulates a lot of the issues with DNA research. We like to think of ourselves as individuals, with the right to know ourselves, but anyone who has looked into the issue of how DNA testing interacts with adoption, or infidelity, or genetic susceptibility to disease, encounters the fact that allowing one person to get the data, denies anyone related (or theoretically related) to them the option of not doing that, or keeping it private if they do. We share DNA. It ties us, and our histories and our decisions, together, even when we would rather it did not. Knowing something about your DNA, tells you something about mine as well. Not being allowed to know about your ancestors, denies me the ability to know something about mine (because we're all related, eventually). As the evidence so far shows, we have been splitting into different races, and then mixing again, for a long long time, and it has happened on every continent, multiple times.
There is also a great deal of discussion about the different things we learn from mitochondrial DNA (inherited from the mother only), Y chromosomes (inherited from the father only), and the rest of our DNA. Looking at all three types of data can tell us things we don't always like to hear about. Like, for example, tales of all of the men in a region being exterminated by the invaders, but the women appear to have survived and reproduced. It is hard to believe that most of that did not resemble ancient tales of rape and pillage. We are, all of us, descended from people who did some very bad things.
Oh, and for you "Highlander" fans, you will be happy to know that the Kurgan people are, in fact, probably the ones who spread the Indo-European languages across two continents.
I also want to point out that Reich makes excellent use of visuals to tell a complex story (or more than one). Maps,, timelines, and all manner of diagrams help us to follow the multiple splitting and merging events, and when and where they happened.
Reich admits early on that much of what he has to tell us, could be modified by more discoveries in the near future, but what we know already is enough to think on for many days. On the whole, though, what we have gotten from this new science so far, is a glimpse into a distant past, well before written history, that was as full of drama and tragedy, adventure and violence and sex as any opera or ancient Greek epic. It was all forgotten, entirely 100% forgotten and lost, for millennia. Until now. Now, like the skeleton in the closet of the human family's old house, it is all coming out.
March 17, 2024
Погледът към ДНК секвенирането и огромната му новоизгряла роля за по-удачното датиране на ключови събития в развитието на човечеството, е занимателен и провокиращ. Историята ни като вид е в нашите гени. А “вид” е по-широко понятие от общоприетото, включващо вече изчезнали клонове като неандерталците и денисовия човек. Всъщност - не напълно изчезнали, тъй като европейците носят около 2% неандерталска ДНК, а азиатците в източната част - немалко денисовска. Но все пак съвременният Homo sapiens е безспорният победител в състезанието по оцеляване.
Авторът честно слага на масата многобройните ограничения пред този нов научен метод за изследване. Като например - и тук всеки върл националист ще завие в протест и обида - че такова нещо като “коренно население” не съществува. Ако изследваш ДНК на дадено население днес, това съвсем не значи, че дълбаеш (много) назад в историята на конкретния географски регион! Просто защото преселенията, миграциите, смесването, изтласкването, измирането или даже умишленото избиване на човешки общности и маси са вечният лайтмотив на човешката история. Географията е горе-долу константа (от разцепването на суперконтинента Пангея насам и с теорията за движението на тектоничните плочи). Но историята - не, тя е вечно движение, и сравнена с бавното време на географията, геологията, климатологията и тектониката, се стрелка с размиваща за окото скорост.
С��мият метод е безкрайно технократски описан - и съответно скучен за прочит, с приспивни увъртания и уточнения. Освен това използваната изходна база за изследване е - меко казано - ограничена. Не са толкова много образците от древна човешка ДНК, които са послужили за оформяне на досегашните изводи за древната ни история. Те идват от предимно западната (и по-развита и спокойна) част на днешния свят. Поради което вратата за резки промени в изводите на база новопостъпила информация е широко отворена. Но дори и на сегашния етап резултатите са интригуващи. И ако в бъдеще се намери автор да доразвие темата с по-малко отплесване в самодоволно описание на собствената си роля е процеса (която е наистина водеща) и на лабораторното оборудване или поименно изброяване на всички свои сътрудници и подпроектите им, прочитът ще бъде доста по-просветляващ и интересен.
March 3, 2021
This may be the definitive popular tract on ancient human population genetics available. It is both rigorous and accessible while thought-provoking and edifying. Completely leaps and bounds beyond its contemporary competitors. I strongly recommend!
September 1, 2018
A perception changing book ... but it contained too much information for my attention capacity. Less than 300 pages of text, but seemed longer. Did a lot of skimming. If I had purchased it, rather than borrowing, it would be read it segments with underlining and marginal comments, and would likely be re-visited multiple times ... amazing science.
Tagged it Dewey 500s, for applied science. Library of Congress catalogs it 572 for human genetics.
"Contents ...
Part I - The Deep History of Our Species
1. How the Genome Explains Who We Are
2. Encounters with Neanderthals
3. Ancient DNA Opens the Floodgates" (This chapter was where book caught my attention.)
Part II - How We Got to Where We Are Today
4. Humanity's Ghosts (Most significant section for me ... multiple new concepts and facts.)
5. The Making of Modern Europe
6. The Collision That Formed India
7. In Search of Native American Ancestors
8. The Genomic Origins of East Asians
9. Rejoining Africa to the Human Story
Part III - The Disruptive Genome
10. The Genomics of Inequality
11. The Genomics of Race and Identity
12. The Future of Ancient DNA
***
Quotes
page 50 - "At the conclusion of the Neanderthal genome project, I am still amazed by the surprises we encountered ... As we continue to do genetic work, we keep encountering more and more patterns that reflect the extraordinary impact this interbreeding has had on the genomes of people living today.
... "Were the Neanderthals the only archaic humans who interbred with our ancestors? Or were there other major hybridizations in our past?" (The test I took revealed a 4% Neanderthal components to my genetics.)
Page 59 - "The Denisova discovery proved that interbreeding between archaic and modern humans during the migration of modern humans from Africa and the Near East was not a freak event. So far, DNA from two archaic human populations--Neanderthals and Denisovans--has been sequenced, and in both cases, the data made it possible to detect hybridization ... that had been previously unknown. I would not be surprised if DNA sequenced from the next newly discovered archaic population will also point to a previously unknown hybridization event."
Page 62 - " ... the archaic people who interbred with the ancestors of New Guineans were not close relative of the Siberian Denisovans. When we examined the genomes of present-day New Guineans and Australians ... we discovered ... a population split that occurred 400,000 to 280,000 years ago. This meant that the ancestors of the Siberian Denisovans separated from the Denisovan lineage that contributed ancestry to New Guineans two-thirds of the way back to the separation of the ancestors of Denisovans from Neanderthals.
... "Most likely there are other Denisovan populations as well that we haven't sampled at all. Maybe we should even consider Neanderthals as part of this broad Denisonvan family.
Page 95 - "The high differentiation of human populations in the Near East ten thousand years ago was a specific instance of a broader pattern across the vast region of West Eurasia ... there were at least four major populations ... farmers of the Fertile Crescent, the farmers of Iran, the hunter-gatherers of central and western Europe, and the hunter-gatherers of eastern Europe. All these populations differed from one another as much as Europeans differ from East Asians today. Scholars ... had they lived ten thousand years ago, would have categorized these groups as 'races,' even though nome of these groups survives in unmixed form today."
... "The fusion of these highly different populations into today's West Eurasians is vividly evident in what might be considered the classic northern European look: blue eyes, light skin, and blond hair. Analysis of ancient DNA data shows that western European hunter-gatherers around eight thousand years ago had blue eyes but dark skin and dark hair, a combination that is rare today. The first farmers of Europe mostly had light skin but dark hair and brown eyes--thus light skin in Europe largely owes its origins to migrating farmers. The earliest known example of the classic European blond hair mutation is in an Ancient North Eurasian from the Lake Baikal region of eastern Siberia from seventeen thousand years ago. The hundreds of millions of copies of this mutation in central and western Europe today likely derive from a massive migration into the region of people bearing Ancient North Eurasian ancestry, an event that is related in the next chapter.
"Surprisingly, the ancient DNA revolution, through its discovery of the pervasiveness of ghost populations and their mixture, is fueling a critique of race ... By demonstrating that the genetic fault lines in West Eurasia between ten thousand and four thousand years ago were entirely different from today's, the ancient DNA revolution has shown that today's classification do not reflect fundamental 'pure' units of biology. Instead, today's divisions are recent phenomena ..."
Page 156 - "If there is anything that scholars studying the history of humans in the Americas agree on, it is that the span of human occupation of the New World has been the blink of an eye relative to the extraordinary length of human occupation of Africa and Eurasia. ... It took until the last ice age for Siberia's northeastern corner to be visited by people with the skills and technology needed to survive there ... Once there, the migrants were able to survive, but they still could not travel south, at least by land, as they were blocked by a wall of glacial ice ... (Some surprised the author did not reference the Beringian Standstill Hypothesis
https://www.thoughtco.com/beringian-s...
In his chapter on Native American Ancestors, Reich explains the limits placed on research the beliefs of contemporary 'Native American." (See Dewar's Bones for perspective Bones: Discovering the First Americans
page 171 - "The first genome-scale study of Native American population history came in 2012, when my laboratory published data on fifty-two diverse populations. A major limitation of the study was that we had no samples at all from the lower forth-eight states of the United States because of anxieties about genetic research on Native Americans ...
"Most of the individuals we studied derived small fractions of their genomes from African or European ancestors in their genomes ... especially in Canada, all the individuals we sampled had at least some non-Native American ancestry.
" ... For forty-seven of the fifty-two populations, we could not detect differences in their relatedness to Asians. This suggested to us that the vast majority of Native Americans today; including all those from Mexico southward, as well as populations from eastern Canada, descend from a single common lineage. (Five remaining populations, all from the Arctic or the Pacific Northwest coast of Alaska and Canada, also had evidence of ancestry from different lineages.) Thus the extraordinary physical differences among Native American groups today are due to evolution since splitting from a common ancestral population, not to immigration from different sources in Eurasia.
Page 176 - "Population Y - The next card dealt from the genetic deck was a complete surprise--at least to us geneticists.
" ... an approximately 11,500-year-old skeleton ... found in Brazil ... more similar to those of indigenous peoples from Australia and New Guinea than to ... Native Americans. ...
"These claims are controversial. ... The experience of Kennewick Man, whose skeleton has morphological affinities to those of Pacific Rim populations but genetically is derived entirely from the same ancestral population as other Native Americans, serves as a great warning--an object lesson about the danger of interpreting morphology as strong evidence of population relationships.
"Nevertheless ... If there were ancient people on the continent who were displaced by First Americans, they may have mixed with the ancestors of present-day populations, leaving some statistical signal in the genomes of people living today.
... "He found two Native American populations, both from the Amazon region of Brazil, that are more closely related to Australasians than to other world populations. ... He estimated that the proportion of ancient ancestry in these populations was small--1 to 6 percent--with the rest being consistent with First American ancestry.
... "It really looked like evidence of a migration into the Americas of an ancient population more closely related to Australians, New Guineans, and Andamanese than to present-day Siberians. We concluded that we had found evidence of a 'ghost' population: a population that no longer exists in unmixed form. We called this 'Population Y' ...
***
Adding comments - In my fantasy world, I have played with a novel about a paddling route that might have existed, following the kayak route of the kelp highway across the north pacific as the end of the last glacial maximum.
For fun, what if humans had developed a connection between a possible civilization on Sunda to the new world, and what if paddlers, perhaps Jomon anjins, returned from the new world to report their findings?
In the Wake of the Jomon: Stone Age Mariners and a Voyage Across the Pacific
Quote from page 184 - "A second genetic revelation about Native American population history is clearest in the Chukchi, a population of far northeastern Siberia that speaks a language unrelated to any spoken in the Americas. My analyses revealed that the Chukchi harbor around 40 percent First American ancestry due to backflow from America to Asia. ... the genetic data clarify that the affinity is due to back-migration, as the Chucki are more closely related to some populations of entirely First American ancestry than to others, a finding that can only be explained if a sublineage of First Americans that originated well after the initial diversification of First American lineages in North America migrated back to Asia. The explanation for this observation is that the Eskimo-Aleut speakerswho established themselves in North America mixed heavily with local Native Americans (who contributed about half their ancestry) and then took their successful way of life back through the Arctic with them to Siberia ... a type of finding that is difficult to prove with archaeology--is the kind of surprise that genetics is in a unique position to deliver."
Tagged it Dewey 500s, for applied science. Library of Congress catalogs it 572 for human genetics.
"Contents ...
Part I - The Deep History of Our Species
1. How the Genome Explains Who We Are
2. Encounters with Neanderthals
3. Ancient DNA Opens the Floodgates" (This chapter was where book caught my attention.)
Part II - How We Got to Where We Are Today
4. Humanity's Ghosts (Most significant section for me ... multiple new concepts and facts.)
5. The Making of Modern Europe
6. The Collision That Formed India
7. In Search of Native American Ancestors
8. The Genomic Origins of East Asians
9. Rejoining Africa to the Human Story
Part III - The Disruptive Genome
10. The Genomics of Inequality
11. The Genomics of Race and Identity
12. The Future of Ancient DNA
***
Quotes
page 50 - "At the conclusion of the Neanderthal genome project, I am still amazed by the surprises we encountered ... As we continue to do genetic work, we keep encountering more and more patterns that reflect the extraordinary impact this interbreeding has had on the genomes of people living today.
... "Were the Neanderthals the only archaic humans who interbred with our ancestors? Or were there other major hybridizations in our past?" (The test I took revealed a 4% Neanderthal components to my genetics.)
Page 59 - "The Denisova discovery proved that interbreeding between archaic and modern humans during the migration of modern humans from Africa and the Near East was not a freak event. So far, DNA from two archaic human populations--Neanderthals and Denisovans--has been sequenced, and in both cases, the data made it possible to detect hybridization ... that had been previously unknown. I would not be surprised if DNA sequenced from the next newly discovered archaic population will also point to a previously unknown hybridization event."
Page 62 - " ... the archaic people who interbred with the ancestors of New Guineans were not close relative of the Siberian Denisovans. When we examined the genomes of present-day New Guineans and Australians ... we discovered ... a population split that occurred 400,000 to 280,000 years ago. This meant that the ancestors of the Siberian Denisovans separated from the Denisovan lineage that contributed ancestry to New Guineans two-thirds of the way back to the separation of the ancestors of Denisovans from Neanderthals.
... "Most likely there are other Denisovan populations as well that we haven't sampled at all. Maybe we should even consider Neanderthals as part of this broad Denisonvan family.
Page 95 - "The high differentiation of human populations in the Near East ten thousand years ago was a specific instance of a broader pattern across the vast region of West Eurasia ... there were at least four major populations ... farmers of the Fertile Crescent, the farmers of Iran, the hunter-gatherers of central and western Europe, and the hunter-gatherers of eastern Europe. All these populations differed from one another as much as Europeans differ from East Asians today. Scholars ... had they lived ten thousand years ago, would have categorized these groups as 'races,' even though nome of these groups survives in unmixed form today."
... "The fusion of these highly different populations into today's West Eurasians is vividly evident in what might be considered the classic northern European look: blue eyes, light skin, and blond hair. Analysis of ancient DNA data shows that western European hunter-gatherers around eight thousand years ago had blue eyes but dark skin and dark hair, a combination that is rare today. The first farmers of Europe mostly had light skin but dark hair and brown eyes--thus light skin in Europe largely owes its origins to migrating farmers. The earliest known example of the classic European blond hair mutation is in an Ancient North Eurasian from the Lake Baikal region of eastern Siberia from seventeen thousand years ago. The hundreds of millions of copies of this mutation in central and western Europe today likely derive from a massive migration into the region of people bearing Ancient North Eurasian ancestry, an event that is related in the next chapter.
"Surprisingly, the ancient DNA revolution, through its discovery of the pervasiveness of ghost populations and their mixture, is fueling a critique of race ... By demonstrating that the genetic fault lines in West Eurasia between ten thousand and four thousand years ago were entirely different from today's, the ancient DNA revolution has shown that today's classification do not reflect fundamental 'pure' units of biology. Instead, today's divisions are recent phenomena ..."
Page 156 - "If there is anything that scholars studying the history of humans in the Americas agree on, it is that the span of human occupation of the New World has been the blink of an eye relative to the extraordinary length of human occupation of Africa and Eurasia. ... It took until the last ice age for Siberia's northeastern corner to be visited by people with the skills and technology needed to survive there ... Once there, the migrants were able to survive, but they still could not travel south, at least by land, as they were blocked by a wall of glacial ice ... (Some surprised the author did not reference the Beringian Standstill Hypothesis
https://www.thoughtco.com/beringian-s...
In his chapter on Native American Ancestors, Reich explains the limits placed on research the beliefs of contemporary 'Native American." (See Dewar's Bones for perspective Bones: Discovering the First Americans
page 171 - "The first genome-scale study of Native American population history came in 2012, when my laboratory published data on fifty-two diverse populations. A major limitation of the study was that we had no samples at all from the lower forth-eight states of the United States because of anxieties about genetic research on Native Americans ...
"Most of the individuals we studied derived small fractions of their genomes from African or European ancestors in their genomes ... especially in Canada, all the individuals we sampled had at least some non-Native American ancestry.
" ... For forty-seven of the fifty-two populations, we could not detect differences in their relatedness to Asians. This suggested to us that the vast majority of Native Americans today; including all those from Mexico southward, as well as populations from eastern Canada, descend from a single common lineage. (Five remaining populations, all from the Arctic or the Pacific Northwest coast of Alaska and Canada, also had evidence of ancestry from different lineages.) Thus the extraordinary physical differences among Native American groups today are due to evolution since splitting from a common ancestral population, not to immigration from different sources in Eurasia.
Page 176 - "Population Y - The next card dealt from the genetic deck was a complete surprise--at least to us geneticists.
" ... an approximately 11,500-year-old skeleton ... found in Brazil ... more similar to those of indigenous peoples from Australia and New Guinea than to ... Native Americans. ...
"These claims are controversial. ... The experience of Kennewick Man, whose skeleton has morphological affinities to those of Pacific Rim populations but genetically is derived entirely from the same ancestral population as other Native Americans, serves as a great warning--an object lesson about the danger of interpreting morphology as strong evidence of population relationships.
"Nevertheless ... If there were ancient people on the continent who were displaced by First Americans, they may have mixed with the ancestors of present-day populations, leaving some statistical signal in the genomes of people living today.
... "He found two Native American populations, both from the Amazon region of Brazil, that are more closely related to Australasians than to other world populations. ... He estimated that the proportion of ancient ancestry in these populations was small--1 to 6 percent--with the rest being consistent with First American ancestry.
... "It really looked like evidence of a migration into the Americas of an ancient population more closely related to Australians, New Guineans, and Andamanese than to present-day Siberians. We concluded that we had found evidence of a 'ghost' population: a population that no longer exists in unmixed form. We called this 'Population Y' ...
***
Adding comments - In my fantasy world, I have played with a novel about a paddling route that might have existed, following the kayak route of the kelp highway across the north pacific as the end of the last glacial maximum.
For fun, what if humans had developed a connection between a possible civilization on Sunda to the new world, and what if paddlers, perhaps Jomon anjins, returned from the new world to report their findings?
In the Wake of the Jomon: Stone Age Mariners and a Voyage Across the Pacific
Quote from page 184 - "A second genetic revelation about Native American population history is clearest in the Chukchi, a population of far northeastern Siberia that speaks a language unrelated to any spoken in the Americas. My analyses revealed that the Chukchi harbor around 40 percent First American ancestry due to backflow from America to Asia. ... the genetic data clarify that the affinity is due to back-migration, as the Chucki are more closely related to some populations of entirely First American ancestry than to others, a finding that can only be explained if a sublineage of First Americans that originated well after the initial diversification of First American lineages in North America migrated back to Asia. The explanation for this observation is that the Eskimo-Aleut speakerswho established themselves in North America mixed heavily with local Native Americans (who contributed about half their ancestry) and then took their successful way of life back through the Arctic with them to Siberia ... a type of finding that is difficult to prove with archaeology--is the kind of surprise that genetics is in a unique position to deliver."
July 2, 2018
This. Was. Excruciating. I finished this by relying on sheer stubbornness. The topic was of interest and I hoped (unreasonably, it seems) that it would improve as I read. It did not. I fell asleep repeatedly trying to read it. I was thrilled to finish. Why?
This is a textbook-like survey of the author’s work using whole DNA as opposed to Y DNA or mitochondrial DNA to analyze ancient bones in an effort to uncover the origin of modern humans. The process is incredibly technical and is really a mathematical exercise using statistical models on decoded DNA. So you’re going to read a lot about statistical tests, models used to analyze migrations of ancient humans, and the challenges inherent in such work. This scientist is less interested in the narrative of human history as it is uncovered by his work and much more devoted to finding new laboratory models.
The introduction was interesting as he laid the foundation for the work to come. But then it deteriorated into an incredible boring tome, broken up occasionally by a useful insight or fact (the presence of “ghost species” being one). Each chapter in the main section of the book was a discrete exploration of specific geographic ranges and what has been found in the DNA there. So there is a section on Europe (Eurasian), India, Africa, Native Americans, Pacific Islanders, East Asia ... with little to connect any of it unless you can recall the mind-numbing detail from a prior chapter. Even the diagrams aren’t especially helpful.
The later chapters, exploring the political and social ramifications of his work — “race”, gender, health risks, future research — were edifying but not enough to redeem the rest of it.
My expectation was for a book similar to “Sapiens” in that it would provide a narrative that helped lay people understand those migrations, interbreeding of long-lost human species, the scope of human history revealed by DNA. Nope. That is not how this read. Mostly, he walked the reader through the technical processes that enabled him to reach some conclusions, the big one being: Humans are impure. A mixed up species with a bunch of other species hidden in our genes. He does challenge the current orthodoxy that populations may have genetic dispositions to certain traits, behaviors, talents. Today’s belief system is built on denying that populations can have genetic differences, primarily because in the past that has been used to discriminate based on “race”. He pushes the reader to realize that we are already finding those differences and will need to have a moral and ethical means to accept those differences without using them as an excuse to reject others.
His discussion of the role of male power in spreading genetic material into populations that were different from them was disturbing in that he completely ignores the reality that much of this “spreading” was the result of raping conquered women. The result is that there is a lot of diversity in the female line of humans and not much in the male. The men who succeeded in leaving their Y chromosomes throughout the world were the ones who were most aggressive and violent as they displaced more peaceful men during human migrations. The implications of this to human history are vital... but he insists on referring to these people as “couples”, as if women always had a voice in choosing those men. He makes that assumption with Thomas Jefferson as well, when discussing race in the U.S. and how so many African Americans came to have Eurasian/European genetic material in them.
Understanding the evolution of modern humans can lead us to a deeper understanding our how our species behaves even today. We will need to look to archeologists and anthropologists for those insights and narratives. Hopefully, they will be able to understand the work of people like this author and to be able to challenge it when appropriate. This book won’t be much help unless they first take a lot of courses in DNA science and statistics. If you, like me, are not thrilled with statistics, avoid this book. The author could have made his points in a book half the size.
This is a textbook-like survey of the author’s work using whole DNA as opposed to Y DNA or mitochondrial DNA to analyze ancient bones in an effort to uncover the origin of modern humans. The process is incredibly technical and is really a mathematical exercise using statistical models on decoded DNA. So you’re going to read a lot about statistical tests, models used to analyze migrations of ancient humans, and the challenges inherent in such work. This scientist is less interested in the narrative of human history as it is uncovered by his work and much more devoted to finding new laboratory models.
The introduction was interesting as he laid the foundation for the work to come. But then it deteriorated into an incredible boring tome, broken up occasionally by a useful insight or fact (the presence of “ghost species” being one). Each chapter in the main section of the book was a discrete exploration of specific geographic ranges and what has been found in the DNA there. So there is a section on Europe (Eurasian), India, Africa, Native Americans, Pacific Islanders, East Asia ... with little to connect any of it unless you can recall the mind-numbing detail from a prior chapter. Even the diagrams aren’t especially helpful.
The later chapters, exploring the political and social ramifications of his work — “race”, gender, health risks, future research — were edifying but not enough to redeem the rest of it.
My expectation was for a book similar to “Sapiens” in that it would provide a narrative that helped lay people understand those migrations, interbreeding of long-lost human species, the scope of human history revealed by DNA. Nope. That is not how this read. Mostly, he walked the reader through the technical processes that enabled him to reach some conclusions, the big one being: Humans are impure. A mixed up species with a bunch of other species hidden in our genes. He does challenge the current orthodoxy that populations may have genetic dispositions to certain traits, behaviors, talents. Today’s belief system is built on denying that populations can have genetic differences, primarily because in the past that has been used to discriminate based on “race”. He pushes the reader to realize that we are already finding those differences and will need to have a moral and ethical means to accept those differences without using them as an excuse to reject others.
His discussion of the role of male power in spreading genetic material into populations that were different from them was disturbing in that he completely ignores the reality that much of this “spreading” was the result of raping conquered women. The result is that there is a lot of diversity in the female line of humans and not much in the male. The men who succeeded in leaving their Y chromosomes throughout the world were the ones who were most aggressive and violent as they displaced more peaceful men during human migrations. The implications of this to human history are vital... but he insists on referring to these people as “couples”, as if women always had a voice in choosing those men. He makes that assumption with Thomas Jefferson as well, when discussing race in the U.S. and how so many African Americans came to have Eurasian/European genetic material in them.
Understanding the evolution of modern humans can lead us to a deeper understanding our how our species behaves even today. We will need to look to archeologists and anthropologists for those insights and narratives. Hopefully, they will be able to understand the work of people like this author and to be able to challenge it when appropriate. This book won’t be much help unless they first take a lot of courses in DNA science and statistics. If you, like me, are not thrilled with statistics, avoid this book. The author could have made his points in a book half the size.
January 4, 2019
David Reich comes off as a sincere guy who loves his work: a puzzle master of human ancestry who is among the first with previously missing pieces. The book explains the methods and the subtle art of obtaining and analyzing ancient DNA using the whole genome. This sequencing illuminates far more than mitochondrial DNA or Y-chromosome research could. If you’re still with me you’ll love this book!
March 15, 2022
Pestera cu Oase din judetul Caras-Severin si hibridizarea ADN-ului
Genomurile non-africanilor de astazi au intre 1,5 si 2,1% ADN de origine Neanderthaliana. Arheologii au aratat modul in care , in Orientul Apropiat, Neanderthalienii si oamenii moderni au facut schimb de locuri ca populatie dominanta, cel putin de doua ori, in perioada cuprinsa intre acum 130 000 si 50 000 de ani si este rezonabil sa presupunem ca ei s-ar fi putut intalni in decursul acestei perioade.
A avut loc, oare, vreo incrucisare in Europa?
In 2014, echipa celebrului Svante Paabo a secventiat ADN-ul dintr-un schelet din Pestera cu Oase. Analiza a aratat ca individul, care a trait acum aproximativ 40 000 de ani, avea un impresionant 6-9% ADN Neanderthalian. Mai mult, unele fragmente de ADN Neandethalian depaseau o treime din lungimea cromozonilor sai, un lant atat de lung si neintrerupt de recombinatii, incat putem fi siguri ca individul din Pestera cu Oase a avut un stramos Neanderthalian adevarat, nu mai mult de sase generatii in urma.
Exista vreo legatura intre individul din Pestera cu Oase si populatia actuala a Romaniei?
Raspunsul este nu. Individul nu a lasat niciun fel de urmasi printre oamenii care traiesc azi in Romania. De fapt, nu a lasat urmasi. A facut parte dintr-o populatie considerata o fundatura evolutiva. Membrii acesteia au ajuns timpuriu in Europa, au inflorit acolo, pentru o scurta perioada, s-au incrucisat cu Nearderthalienii, iar apoi au disparut.
Alte carti de antropologie genetica:
-"Povestea secreta a speciei umane. Cum ne sunt modelate identitatea si viitorul de ADN si de istorie" de Christine Kenneally
-"Scurta istorie a tuturor. Ce povesti spun genele noastre" de Adam Rutherford
-"Odiseea genelor. Aventura speciei umane" de Evelyne Heyer
Genomurile non-africanilor de astazi au intre 1,5 si 2,1% ADN de origine Neanderthaliana. Arheologii au aratat modul in care , in Orientul Apropiat, Neanderthalienii si oamenii moderni au facut schimb de locuri ca populatie dominanta, cel putin de doua ori, in perioada cuprinsa intre acum 130 000 si 50 000 de ani si este rezonabil sa presupunem ca ei s-ar fi putut intalni in decursul acestei perioade.
A avut loc, oare, vreo incrucisare in Europa?
In 2014, echipa celebrului Svante Paabo a secventiat ADN-ul dintr-un schelet din Pestera cu Oase. Analiza a aratat ca individul, care a trait acum aproximativ 40 000 de ani, avea un impresionant 6-9% ADN Neanderthalian. Mai mult, unele fragmente de ADN Neandethalian depaseau o treime din lungimea cromozonilor sai, un lant atat de lung si neintrerupt de recombinatii, incat putem fi siguri ca individul din Pestera cu Oase a avut un stramos Neanderthalian adevarat, nu mai mult de sase generatii in urma.
Exista vreo legatura intre individul din Pestera cu Oase si populatia actuala a Romaniei?
Raspunsul este nu. Individul nu a lasat niciun fel de urmasi printre oamenii care traiesc azi in Romania. De fapt, nu a lasat urmasi. A facut parte dintr-o populatie considerata o fundatura evolutiva. Membrii acesteia au ajuns timpuriu in Europa, au inflorit acolo, pentru o scurta perioada, s-au incrucisat cu Nearderthalienii, iar apoi au disparut.
Alte carti de antropologie genetica:
-"Povestea secreta a speciei umane. Cum ne sunt modelate identitatea si viitorul de ADN si de istorie" de Christine Kenneally
-"Scurta istorie a tuturor. Ce povesti spun genele noastre" de Adam Rutherford
-"Odiseea genelor. Aventura speciei umane" de Evelyne Heyer
April 16, 2019
This book may well go down as one of the classics of our times. Unfortunately, for me the book was considerably disappointing, despite the wealth of information and concepts that it describes. Reason behind that feeling had been summed up by the author himself at the end of the book: the study of ancient DNA, and thus this book, had been almost entirely Eurocentric.
Also, the book turned out to be rather unnecessarily ruminating over philosophical aspects of various findings, while the same ground had been covered by Yuval Noah Harari and Carl Zimmer in their astonishing works in a far more interesting and dramatic manner. It seems that top-notch scientists, even while talking about their own findings and implications, tend to be somewhat conservative and boring.
Last but not the least, while devoting chapter after chapter on Europe and Neanderthals or their absence, the book exhausts India in thirty odd pages. In that single chapter it tries to capture the issues of caste, genetics, movements within the sub-continent and sundry others, while glossing over key issues like:
1. Who were Harappans?
2. What might have happened to them?
These issues have considerably dampened my enthusiasm in this area. It seems, as mentioned by that old saying, I would have to keep searching for a better, more reliable and focused book on the study of ancient DNA and its findings.
CHARAIVETI.
Also, the book turned out to be rather unnecessarily ruminating over philosophical aspects of various findings, while the same ground had been covered by Yuval Noah Harari and Carl Zimmer in their astonishing works in a far more interesting and dramatic manner. It seems that top-notch scientists, even while talking about their own findings and implications, tend to be somewhat conservative and boring.
Last but not the least, while devoting chapter after chapter on Europe and Neanderthals or their absence, the book exhausts India in thirty odd pages. In that single chapter it tries to capture the issues of caste, genetics, movements within the sub-continent and sundry others, while glossing over key issues like:
1. Who were Harappans?
2. What might have happened to them?
These issues have considerably dampened my enthusiasm in this area. It seems, as mentioned by that old saying, I would have to keep searching for a better, more reliable and focused book on the study of ancient DNA and its findings.
CHARAIVETI.
August 16, 2020
Who We Are and How We Got Here: Ancient DNA and the new Science of the Human Past, David Reich, 2018. ISBN 9781101870327, Dewey 572.86, Library-of-Congress QH431.
Inconsistent claims: "Mitochondrial Eve," the most recent one woman all humans alive today descend from, lived about 160,000 years ago. And yet--the present San people of southern Africa split off from West Africans and all the rest of us, 300,000-250,000 years ago. These two claims can't both be true. He says nothing about the contradiction. pp. 2, 13.
Assumes each mutation (any change from one letter--A, G, C, or T--to any of the other three) happened only once, so all of us who have it, descend from one person. p. 18. Seems to me an unwarranted assumption.
"Across chromosomes 1-22, the most recent shared ancestor for all present-day people ranges mostly between 5 million and 1 million years ago, and nowhere is it estimated to be more recent than 320,000 years ago." p. 16.
Chromosomes aren't all passed whole from parent to child. Your parents each got 23 chromosomes from each of their parents. But your parents didn't give you a full copy of one or the other grandparental version of every chromosome. Instead the 23 chromosomes you got from your mother were assembled from, on average, 68 chunks of DNA, each chunk being all or part of a chromosome from one or other of her parents. (Her 23 chromosomes were snipped in, on average, a total of 45 places.) The 23 sperm chromosomes were cut in, on average, 26 places. So your dad bequeathed you 49 chunks of DNA, each chunk from one or the other of his parents. There's also mitochondrial DNA (maternal). In all you have about 118 DNA chunks, each from one of your grandparents. (46 chromosomes + mitochondrial DNA + about 71 chromosome cuts).
The splices can be in different places in successive generations. p. 11. So from g generations back, you inherited a total of 47 + 71(g - 1) chunks of DNA. The author says this wrong on page 12, "118 DNA stretches one generation back, 189 two generations back, … ." But the 118 chunks are already from your grandparents.
This means the maximum number of your ancestors, g generations back, who could have contributed DNA to you is the lesser of:
2^g, or
47 + 71(g - 1), or
the world population at the time:
https://www.wolframalpha.com/input/?i...
https://www.wolframalpha.com/input/?i...
Does not mention the Toba volcanic eruption around 70,000 years ago that killed very nearly all humans. Writing on human prehistory, how can you not?
https://en.m.wikipedia.org/wiki/Toba_...
Ascribes too much to DNA as a cause: "In 2010, geneticists analyzed genomes of 180,000 people with measured heights, and found 180 genetic changes that are more common in shorter people. This means that these changes, or ones nearby, contribute directly to reduced height. In 2012, a study showed that at the 180 changes, southern Europeans tend to have the versions that reduce height … the only explanation is natural selection for increased height in northern Europeans or decreased height in southern Europeans." p. 19.
No, southern Europe is also poorer. Childhood nutrition has a tremendous effect on height. One example: during WWII, German taking of French crops malnourished the French: average height of boys dropped by 7 centimeters (2.75 inches), and of girls by 11 centimeters (4.33 inches). Antony Beevor, /The Second World War/, p. 425.
Having southern European DNA is /correlated/ to lower height. Doesn't prove a cause.
Again: "A 2016 study analyzed the genomes of several thousand present-day Britons and found natural selection for increased height, blonder hair, bluer eyes, larger infant head size …" p. 20. These were the Danes and Norse who conquered Britain! They conquered not because they had blond hair, nor even because they were tall, but because they were desperate. Britons succumbed not because they were brown-haired, nor even because they were short, but because they for centuries thrived by farming and herding, without having to hack their neighbors to bits. So they weren't ready to repel even the much-less-numerous Norse.
If the conquerors' descendants have been lording it ever since, it need not be because of their inherited DNA, but because of their inherited status.
The author overreaches, finding DNA as the cause of everything.
You need other sources; the book is inadequate:
Restriction sites are places where researchers snip the genome. The DNA-fragment-ends next to (associated with) these sites, Restriction-site-Associated DNA (RAD) are pieces researchers compare, one genome to another:
https://en.m.wikipedia.org/wiki/Restr...
He assumes that the mutation rate--probability of a random genetic change, per generation, per location in the genome--is the same everywhere in the genome. AND that all those changes are still there, everywhere in the genome. To the contrary, mutations that happen in a location that codes for an essential protein, and cause the failure of that function, /cannot/ persist. By contrast, mutations in the large stretches of so-called "junk DNA" that seem not to code for proteins, all stay.
So the author's claim that we all got our mitochondria from one woman who lived 160,000 years ago, and our Y chromosomes from a man who lived similarly recently, while the rest of our genome comes from multiple ancestors living millions of years ago--seems to rest on misinterpreted data.
The large chromosomes have genetic space to accumulate any mutations that occur, without damage to the organism. The mitochondria and Y chromosome don't.
The similarities of everyone's mitochondria and Y chromosomes need not mean a recent ancestor, but rather nonsurvival of mutations.
There can be persisting mutations only where they don't hurt the organism. Anything essential can't randomly mutate and survive.
As in, the overall mechanism of protein synthesis is fundamental to life, and so is universally conserved with only trivial differences between humans and hydrothermal bacteria.
--The Vital Question: Energy, Evolution, and the Origins of Complex Life, Nick Lane, chapter 4, footnote 1, p. 123 of 360
The mutation rate is assumed to be 1.25*10^-8 per generation "per site," they don't say what a site is: Sheehan, Harris, & Song, p. 656. Estimating Variable Effective Population Sizes from Multiple Genomes: A Sequentially Markov
Conditional Sampling Distribution Approach, 2013.
https://www.google.com/url?sa=t&s...
The math leading to the author's estimates of antiquity of most-recent shared ancestor, starts from this presumption:
Assume "each member of a generation chooses its mother at random from the previous generation, the choices of the different members being independent." If so, two members of the same generation have a probability (1 - 1/M)^g of having different ancestors g generations back, with M mothers per generation.
But the author doesn't tell us that. from Origins of the Coalescent: 1974-1982,
J. F. C. Kingman,
GENETICS December 1, 2000 vol. 156 no. 4 1461-1463
https://www.genetics.org/content/156/...
This is the kind of model used to estimate how far back people shared a common ancestor.
Here's the plot for 10,000 mothers each generation, over 100,000 generations:
https://www.wolframalpha.com/input/?i...
The rate of differences between humans & Neanderthals is about 1 per 600 letters. p. 31.
There is no bibliography. The notes are mainly just journal-article citations.
Self-congratulatory tone.
A few bone fragments found in Denisov Cave in the Altai Mountains in Siberia yielded DNA of 30,000-to-50,000-years-ago humans now called Denisovans. The author's team found that present-day aboriginal Australians & New Guineans have 5% Denisovan ancestry, while other Asians have a fraction of a percent, Europeans & Africans none. The author says the idea that Denisovans interbred in or near tropical Oceanea with our other ancestors is "hard to square with an absence of artifacts or big-skulled skeletons in the region!!??" pp. 61-62. So he thinks the interbreeding happened elsewhere. Yet even in a Siberian cave we have only a pinky bone and a tooth. No skull. No skeleton. In the tropics, or even in summer in the north woods, remains don't last long. Scavengers & decay see to it. And even recent Aboriginal Australians & New Guineans haven't made a lot of durable artifacts.
Says 5300 years ago (3300 BCE) is "thousands of years before the arrival of writing." p. 99. Or not: "writing may have independently developed in at least four ancient civilizations: Mesopotamia (between 3400 and 3100 BC), Egypt (around 3250 BC) … ." https://en.m.wikipedia.org/wiki/Histo...
Inconsistent claims: "Mitochondrial Eve," the most recent one woman all humans alive today descend from, lived about 160,000 years ago. And yet--the present San people of southern Africa split off from West Africans and all the rest of us, 300,000-250,000 years ago. These two claims can't both be true. He says nothing about the contradiction. pp. 2, 13.
Assumes each mutation (any change from one letter--A, G, C, or T--to any of the other three) happened only once, so all of us who have it, descend from one person. p. 18. Seems to me an unwarranted assumption.
"Across chromosomes 1-22, the most recent shared ancestor for all present-day people ranges mostly between 5 million and 1 million years ago, and nowhere is it estimated to be more recent than 320,000 years ago." p. 16.
Chromosomes aren't all passed whole from parent to child. Your parents each got 23 chromosomes from each of their parents. But your parents didn't give you a full copy of one or the other grandparental version of every chromosome. Instead the 23 chromosomes you got from your mother were assembled from, on average, 68 chunks of DNA, each chunk being all or part of a chromosome from one or other of her parents. (Her 23 chromosomes were snipped in, on average, a total of 45 places.) The 23 sperm chromosomes were cut in, on average, 26 places. So your dad bequeathed you 49 chunks of DNA, each chunk from one or the other of his parents. There's also mitochondrial DNA (maternal). In all you have about 118 DNA chunks, each from one of your grandparents. (46 chromosomes + mitochondrial DNA + about 71 chromosome cuts).
The splices can be in different places in successive generations. p. 11. So from g generations back, you inherited a total of 47 + 71(g - 1) chunks of DNA. The author says this wrong on page 12, "118 DNA stretches one generation back, 189 two generations back, … ." But the 118 chunks are already from your grandparents.
This means the maximum number of your ancestors, g generations back, who could have contributed DNA to you is the lesser of:
2^g, or
47 + 71(g - 1), or
the world population at the time:
https://www.wolframalpha.com/input/?i...
https://www.wolframalpha.com/input/?i...
Does not mention the Toba volcanic eruption around 70,000 years ago that killed very nearly all humans. Writing on human prehistory, how can you not?
https://en.m.wikipedia.org/wiki/Toba_...
Ascribes too much to DNA as a cause: "In 2010, geneticists analyzed genomes of 180,000 people with measured heights, and found 180 genetic changes that are more common in shorter people. This means that these changes, or ones nearby, contribute directly to reduced height. In 2012, a study showed that at the 180 changes, southern Europeans tend to have the versions that reduce height … the only explanation is natural selection for increased height in northern Europeans or decreased height in southern Europeans." p. 19.
No, southern Europe is also poorer. Childhood nutrition has a tremendous effect on height. One example: during WWII, German taking of French crops malnourished the French: average height of boys dropped by 7 centimeters (2.75 inches), and of girls by 11 centimeters (4.33 inches). Antony Beevor, /The Second World War/, p. 425.
Having southern European DNA is /correlated/ to lower height. Doesn't prove a cause.
Again: "A 2016 study analyzed the genomes of several thousand present-day Britons and found natural selection for increased height, blonder hair, bluer eyes, larger infant head size …" p. 20. These were the Danes and Norse who conquered Britain! They conquered not because they had blond hair, nor even because they were tall, but because they were desperate. Britons succumbed not because they were brown-haired, nor even because they were short, but because they for centuries thrived by farming and herding, without having to hack their neighbors to bits. So they weren't ready to repel even the much-less-numerous Norse.
If the conquerors' descendants have been lording it ever since, it need not be because of their inherited DNA, but because of their inherited status.
The author overreaches, finding DNA as the cause of everything.
You need other sources; the book is inadequate:
Restriction sites are places where researchers snip the genome. The DNA-fragment-ends next to (associated with) these sites, Restriction-site-Associated DNA (RAD) are pieces researchers compare, one genome to another:
https://en.m.wikipedia.org/wiki/Restr...
He assumes that the mutation rate--probability of a random genetic change, per generation, per location in the genome--is the same everywhere in the genome. AND that all those changes are still there, everywhere in the genome. To the contrary, mutations that happen in a location that codes for an essential protein, and cause the failure of that function, /cannot/ persist. By contrast, mutations in the large stretches of so-called "junk DNA" that seem not to code for proteins, all stay.
So the author's claim that we all got our mitochondria from one woman who lived 160,000 years ago, and our Y chromosomes from a man who lived similarly recently, while the rest of our genome comes from multiple ancestors living millions of years ago--seems to rest on misinterpreted data.
The large chromosomes have genetic space to accumulate any mutations that occur, without damage to the organism. The mitochondria and Y chromosome don't.
The similarities of everyone's mitochondria and Y chromosomes need not mean a recent ancestor, but rather nonsurvival of mutations.
There can be persisting mutations only where they don't hurt the organism. Anything essential can't randomly mutate and survive.
As in, the overall mechanism of protein synthesis is fundamental to life, and so is universally conserved with only trivial differences between humans and hydrothermal bacteria.
--The Vital Question: Energy, Evolution, and the Origins of Complex Life, Nick Lane, chapter 4, footnote 1, p. 123 of 360
The mutation rate is assumed to be 1.25*10^-8 per generation "per site," they don't say what a site is: Sheehan, Harris, & Song, p. 656. Estimating Variable Effective Population Sizes from Multiple Genomes: A Sequentially Markov
Conditional Sampling Distribution Approach, 2013.
https://www.google.com/url?sa=t&s...
The math leading to the author's estimates of antiquity of most-recent shared ancestor, starts from this presumption:
Assume "each member of a generation chooses its mother at random from the previous generation, the choices of the different members being independent." If so, two members of the same generation have a probability (1 - 1/M)^g of having different ancestors g generations back, with M mothers per generation.
But the author doesn't tell us that. from Origins of the Coalescent: 1974-1982,
J. F. C. Kingman,
GENETICS December 1, 2000 vol. 156 no. 4 1461-1463
https://www.genetics.org/content/156/...
This is the kind of model used to estimate how far back people shared a common ancestor.
Here's the plot for 10,000 mothers each generation, over 100,000 generations:
https://www.wolframalpha.com/input/?i...
The rate of differences between humans & Neanderthals is about 1 per 600 letters. p. 31.
There is no bibliography. The notes are mainly just journal-article citations.
Self-congratulatory tone.
A few bone fragments found in Denisov Cave in the Altai Mountains in Siberia yielded DNA of 30,000-to-50,000-years-ago humans now called Denisovans. The author's team found that present-day aboriginal Australians & New Guineans have 5% Denisovan ancestry, while other Asians have a fraction of a percent, Europeans & Africans none. The author says the idea that Denisovans interbred in or near tropical Oceanea with our other ancestors is "hard to square with an absence of artifacts or big-skulled skeletons in the region!!??" pp. 61-62. So he thinks the interbreeding happened elsewhere. Yet even in a Siberian cave we have only a pinky bone and a tooth. No skull. No skeleton. In the tropics, or even in summer in the north woods, remains don't last long. Scavengers & decay see to it. And even recent Aboriginal Australians & New Guineans haven't made a lot of durable artifacts.
Says 5300 years ago (3300 BCE) is "thousands of years before the arrival of writing." p. 99. Or not: "writing may have independently developed in at least four ancient civilizations: Mesopotamia (between 3400 and 3100 BC), Egypt (around 3250 BC) … ." https://en.m.wikipedia.org/wiki/Histo...
April 19, 2022
David Reich is a geneticist and a leading scientist in the field of genomic study of the ancient human population. What Reich called “genomic revolution” has profoundly changed our understanding of deep human history. This book is a summary of this revolution, where genomic analysis of ancient humans is applied in archeology, linguistics, and human migration.
The book is organised by continent and by chronological order. Many eye opening findings. For examples:
1. The hybrid of Neanderthals and Home Sapiens had reduced fertility due to the speciation.
2. 5000 to 4000 years ago Yamnaya culture from Russian steppes migrated to Europe, mixed with local hunter-gatherers and replaced their relatively peaceful culture. They are the strongest candidate for the origin of the proto-Indo-European language, whose culture was violent, hierarchical and men dominated.
3. It is true that populations in the Indian subcontinent today are results of multiple waves of migrations from the west.
4. The North American population is more closely related to Europeans than to East Asians today, due to a ghost population in North East Asian who later migrated to North America and Europe.
5. The American continent was populated before the First American arrived around 13000 years ago, but we don’t know why they were, yet.
6. Population migration and culture adaptation may not always go hand in hand. The ancient culture originated in Taiwan spread throughout Mesopotamia but probably not their genes.
7. What population bottlenecks mean in genetics. A larger presence of a certain mutation in a population is not always the result of natural selection. It can also be the result of the founding individuals who happened to carry that mutation.
Most important of all, we, the modern humans, are a single human race. We are all mixed.
What I find most intriguing is Part III, the genomics of inequality, race and identity. Race is such a hotly contested topic in today’s social and political landscape, but David Reich is brave enough to tackle it. He quotes David Goldstein that the US census race category is so weakly predictive in most biological outcomes that they do not have long term value. Goldstein thinks it is useful for now but it should be replaced in the future by testing individuals for genetic mutations. Reich agrees with Goldstein but he also believes genome wide association studies are meaningful nevertheless, if only to understand ourselves and our past. Most importantly, there is already data available. If scientists ignore it, the political right will use it to attack the credibility of academia and interpret data to their benefit. Reich then argues against Nicholas Wade and his book, A Troublesome Inheritance: Genes, Race and Human History. Although he agrees with Wade’s assessment that current academia orthodoxy tends to ignore the genetic differences between populations, he disagrees with Wade’s conclusions and he thinks Wade jumps to racial stereotypes without scientific evidence. In other words, Wade’s argument is an either-or fallacy, a false dichotomy.
I understand and agree with his stance, but I am not confident in the prospect of improvement in public understanding of issues like gender and race any time soon. Perhaps I am cynical. Scientist or not, we all make mistakes. People have baggage. They are shaped by different environments. Rational thinking, systematic thinking, statistical thinking and thinking of long term consequences are hard skills to learn and to apply.
The book is organised by continent and by chronological order. Many eye opening findings. For examples:
1. The hybrid of Neanderthals and Home Sapiens had reduced fertility due to the speciation.
2. 5000 to 4000 years ago Yamnaya culture from Russian steppes migrated to Europe, mixed with local hunter-gatherers and replaced their relatively peaceful culture. They are the strongest candidate for the origin of the proto-Indo-European language, whose culture was violent, hierarchical and men dominated.
3. It is true that populations in the Indian subcontinent today are results of multiple waves of migrations from the west.
4. The North American population is more closely related to Europeans than to East Asians today, due to a ghost population in North East Asian who later migrated to North America and Europe.
5. The American continent was populated before the First American arrived around 13000 years ago, but we don’t know why they were, yet.
6. Population migration and culture adaptation may not always go hand in hand. The ancient culture originated in Taiwan spread throughout Mesopotamia but probably not their genes.
7. What population bottlenecks mean in genetics. A larger presence of a certain mutation in a population is not always the result of natural selection. It can also be the result of the founding individuals who happened to carry that mutation.
Most important of all, we, the modern humans, are a single human race. We are all mixed.
What I find most intriguing is Part III, the genomics of inequality, race and identity. Race is such a hotly contested topic in today’s social and political landscape, but David Reich is brave enough to tackle it. He quotes David Goldstein that the US census race category is so weakly predictive in most biological outcomes that they do not have long term value. Goldstein thinks it is useful for now but it should be replaced in the future by testing individuals for genetic mutations. Reich agrees with Goldstein but he also believes genome wide association studies are meaningful nevertheless, if only to understand ourselves and our past. Most importantly, there is already data available. If scientists ignore it, the political right will use it to attack the credibility of academia and interpret data to their benefit. Reich then argues against Nicholas Wade and his book, A Troublesome Inheritance: Genes, Race and Human History. Although he agrees with Wade’s assessment that current academia orthodoxy tends to ignore the genetic differences between populations, he disagrees with Wade’s conclusions and he thinks Wade jumps to racial stereotypes without scientific evidence. In other words, Wade’s argument is an either-or fallacy, a false dichotomy.
I understand and agree with his stance, but I am not confident in the prospect of improvement in public understanding of issues like gender and race any time soon. Perhaps I am cynical. Scientist or not, we all make mistakes. People have baggage. They are shaped by different environments. Rational thinking, systematic thinking, statistical thinking and thinking of long term consequences are hard skills to learn and to apply.
April 21, 2018
Having read earlier books on this topic by Svante Paabo, Spencer Wells and others I was anxious to read something current. I wasn't disappointed. This, as others have said, is an excellent summary of the state of genetic research using ancient DNA to determine how we all got to where we are today. The only downside is that the rate of advancement in the field--as the author states--is so high at the moment that unless you read this within two to three years of publication it may well be out of date.
The author emphasizes the importance of "whole genome" research, pointing out that the companies providing genetic information to the public today are primarily using only mitochondrial and Y-chromosome DNA, which only tell the story of two lineages out of thousands.
Some key points for me were that the history of humankind is not like a tree with branches that separate and never rejoin. Ancient DNA has revealed that it is more like a trellis or a braided stream where lineages branch off but then often merge at some later point, Homo sapiens and Neanderthals being just one example of many.
Another interesting point was that Northern Europeans are more closely related to Native Americans than they are to East Asians. This is due to an ancient population of north Eurasians that no longer exist, but when they did they spread west and east across Europe and Siberia and thus contributed ancestry to the people that left northeast Asia to cross Beringia as well as modern north Europeans. Similar stories are recounted for other modern day groups such as those from India and Oceania.
One final story of personal interest is that ancient DNA research has revealed that the sub-Saharan tribe that is most closely related to all non-African people today are the Hadza hunter-gatherers of Tanzania. Coincidentally I was in Tanzania a little over a year ago and had the pleasure of going on a hunt with a small band of Hadza men. They are rapidly being squeezed out of their ancestral hunting territories and number less than 1500 individuals today, so it was very special to spend a day with them.
This is a very worthwhile read, but don't leave it your bookshelf unread for too long.
The author emphasizes the importance of "whole genome" research, pointing out that the companies providing genetic information to the public today are primarily using only mitochondrial and Y-chromosome DNA, which only tell the story of two lineages out of thousands.
Some key points for me were that the history of humankind is not like a tree with branches that separate and never rejoin. Ancient DNA has revealed that it is more like a trellis or a braided stream where lineages branch off but then often merge at some later point, Homo sapiens and Neanderthals being just one example of many.
Another interesting point was that Northern Europeans are more closely related to Native Americans than they are to East Asians. This is due to an ancient population of north Eurasians that no longer exist, but when they did they spread west and east across Europe and Siberia and thus contributed ancestry to the people that left northeast Asia to cross Beringia as well as modern north Europeans. Similar stories are recounted for other modern day groups such as those from India and Oceania.
One final story of personal interest is that ancient DNA research has revealed that the sub-Saharan tribe that is most closely related to all non-African people today are the Hadza hunter-gatherers of Tanzania. Coincidentally I was in Tanzania a little over a year ago and had the pleasure of going on a hunt with a small band of Hadza men. They are rapidly being squeezed out of their ancestral hunting territories and number less than 1500 individuals today, so it was very special to spend a day with them.
This is a very worthwhile read, but don't leave it your bookshelf unread for too long.
July 13, 2020
I selected this book expecting a straightforward review of the current science regarding the development of our species. While Professor Reich largely met this expectation, he unfortunately delved into the politics that seems inextricably and unfortunately attached to genetic studies today; I had hoped, in error it turns out, to have left this debate behind with Michael Staub’s The Mismeasure of Minds. I’ve mentioned previously that genetic researchers seem to be walking a tightrope; one politically incorrect statement, one unpalatable observation, whatever the scientific merit, and their career is possibly ended. Professor Reich, however, makes a strong case for the pursuit of truth despite the risks; if it were me, I’d avoid the field entirely.
I conclude from this work that we as individuals are the product of a far greater degree of genetic admixture than previously acknowledged. Rather than single branches developing off a common trunk, Professor Reich notes we have developed through an interlaced latticework; societies have migrated far and wide, some notable recent groups even leaving no current trace of their existence, referred to in the field as ghost populations. These findings puncture forcefully the notion of racial purity, indeed purity of any sort; this world is one giant blender of DNA.
An asymmetry came to mind in reading this book. I thought about how much we seem concerned for our ancestors, the desire for our own personal stories, and how little we are concerned for our future generations. I’m fairly certain my ancestors in the 1700s paid zero mind to me; so why am I so interested in them. Why is it we spend so little energy thinking of the generations to come and so much thinking of the generations that preceded?
I conclude from this work that we as individuals are the product of a far greater degree of genetic admixture than previously acknowledged. Rather than single branches developing off a common trunk, Professor Reich notes we have developed through an interlaced latticework; societies have migrated far and wide, some notable recent groups even leaving no current trace of their existence, referred to in the field as ghost populations. These findings puncture forcefully the notion of racial purity, indeed purity of any sort; this world is one giant blender of DNA.
An asymmetry came to mind in reading this book. I thought about how much we seem concerned for our ancestors, the desire for our own personal stories, and how little we are concerned for our future generations. I’m fairly certain my ancestors in the 1700s paid zero mind to me; so why am I so interested in them. Why is it we spend so little energy thinking of the generations to come and so much thinking of the generations that preceded?
Displaying 1 - 30 of 768 reviews