Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past by David Reich (PDF)

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A groundbreaking book about how ancient DNA has profoundly changed our understanding of human history. Geneticists like David Reich have made astounding advances in the field of genomics, which is proving to be as important as archeology, linguistics, and written records as a means to understand our ancestry. In Who We Are and How We Got Here, Reich allows readers to discover how the human genome provides not only all the information a human embryo needs to develop but also the hidden story of our species. Reich delves into how the genomic revolution is transforming our understanding of modern humans and how DNA studies reveal deep inequalities among different populations, between the sexes, and among individuals. Provocatively, Reich’s book suggests that there might very well be biological differences among human populations but that these differences are unlikely to conform to common stereotypes. Drawing upon revolutionary findings and unparalleled scientific studies, Who We Are and How We Got Here is a captivating glimpse into humankind—where we came from and what that says about our lives today.

User’s Reviews

Editorial Reviews: Review “Few subjects fascinate us as much as human origins. . . . If you want to understand our origins over the course of the last 100,000 years, this book will be the best up-to-date account for you.” —Jared Diamond, The New York Times Book Review”The work in [Reich’s] lab has reshaped our understanding of human prehistory. . . . He and his colleagues have shed light on the peopling of the planet and the spread of agriculture, among other momentous events.”—Carl Zimmer, The New York Times”Reich documents an extraordinary moment in the history of science. . . . A potential political bombshell.”—The Wall Street Journal”In Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past, David Reich . . . introduces us to the 21st-century Rosetta Stone: ancient DNA, which will do more for our understanding of prehistory than radiocarbon dating did… Who We Are and How We Got Here is less than 300 pages of text, but it is packed with startling facts and novel revelations that overturn the conventional expectations of both science and common sense.”—The National Review“An excerpt from David Reich’s new book, Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past, recently touched off a media and cultural firestorm in the United States. Appearing as an op-ed in The New York Times, ‘How Genetics is Changing Our Understanding of “Race”’, it had Reich stating that he is ‘worried that well-meaning people who deny the possibility of substantial biological differences among human populations are digging themselves into an indefensible position, one that will not survive the onslaught of science.’ This was not unlike tossing a grenade into the public square. But perched at Harvard, as one of his generation’s most eminent human population geneticists, Reich will move forward unscathed. The reason is simple: Who We Are . . . is mostly not a controversial book, but a wondrous one. It sheds light on the nascent field of ancient DNA, paleogenetics, which is exposing the human past by tracing population histories. Give a paleogeneticist a single genome, and they will unfurl the history of whole peoples.”—India Today”Ancient DNA is rewriting human (and Neanderthal) history. The genomes of the long dead are turning up all sorts of unexpected and controversial findings. Who We Are and How We Got Here, charts the myriad ways the study of ancient DNA is lobbing bombs into the halls of established wisdom.”—The Atlantic”A thrilling account of mapping humans through time and place. . . . Genomics and statistics have drawn back the curtain on the sort of sex and power struggles you’d expect in Game of Thrones. . . . We do need a non-loaded way to talk about genetic diversity and similarities in populations. This book goes some way to starting that conversation.”—Nature“In this comprehensive and provocative book, David Reich exhumes and examines fundamental questions about our origin and future using powerful evidence from human genetics. What does ‘race’ mean in 2018? How alike and how unlike are we? What does identity mean? Reich’s book is sobering and clear-eyed, and, in equal parts, thrilling and thought provoking. There were times that I had to stand up and clear my thoughts to continue reading this astonishing and important book.”—Siddhartha Mukherjee, Pulitzer Prize-winning author of The Emperor of All Maladies “Reich’s book reads like notes from the frontline of the ‘Ancient DNA Revolution’ with all the spellbinding drama and intrigue that come with such a huge transformation in our understanding of human history.”—Anne Wojcicki, CEO and Co-Founder of 23andMe“In just five years, the study of ancient DNA has transformed our understanding of world prehistory. The geneticist David Reich, one of the pioneers in this field, here gives the brilliantly lucid first account of the resulting new view of human origins and of the later dispersals that went on to shape the modern world.”—Colin Renfrew, Disney Professor of Archeology Emeritus, University of Cambridge “Reich’s magisterial book gives a riveting account of human prehistory and history through the new lens provided by ancient DNA data. The story of human populations, as he shows, is ever one of widespread and repeated mixing, debunking the fiction of ‘pure’ populations.”—Molly Przeworski, Professor of Biological Sciences, Columbia University “This breathtaking book dramatically revises our understanding of the deep history of our species in our African homeland and beyond. Beautifully written, it reads like a detective novel and demonstrates a hard truth that often makes many of us uncomfortable: not only are all human beings mixed, but our intuitive understanding of the evolution of the population structure of the world around us is not to be trusted.”—Henry Louis Gates Jr., University Professor, Harvard University, and Executive Producer of Finding Your Roots “This absorbing book will blow you away with its rich and astounding account of where we came from and why that matters. Reich tells the surprising story of how humans got to every corner of the planet, which was revealed only after he and other scientists unlocked the secrets of ancient DNA. The courageous, compassionate, and highly personal climax will transform how you think about the meaning of ancestry and race.”—Daniel E. Lieberman, Professor of Human Evolutionary Biology, Harvard University, and author of The Story of the Human Body: Evolution, Health, and Disease “Powerful writing and extraordinary insights animate this endlessly fascinating account, by a world scientific leader, of who we modern humans are and how our ancestors arrived in the diverse corners of the world. I could not put the book down.”—Robert Weinberg, Professor of Biology, Massachusetts Institute of Technology”David Reich uses the power of modern genome analysis to show the fascinating complexity of human migration and history. By letting the data lead him, he treads a narrow path between racists and xenophobes on one side and left-wing ideologues on the other. Although many of his conclusions will be controversial, he starts a necessary conversation about what modern genome analysis can tell us about the variability of human populations.” —Sir Venki Ramakrishnan, Nobel Laureate and President of the Royal Society, London[Praise from the UK]:”Remarkable. . . . Spectacular. . . . In making constant new discoveries about humanity, Reich and his Harvard team are now plunging into uncharted academic waters. . . . Reich’s influence in this field has been immense and the output of his department monumental. . . . Thrilling in its clarity and its scope.”—The Guardian”David Reich of Harvard Medical School is one of the leading lights in the field of ancient DNA. His team’s work has cast a new perspective on human history, reconstructing the epic migrations and genetic exchanges that shaped the people of different regions worldwide.”—BBC”This is a compendious book . . . its importance cannot be overstated and neither can some of its best stories.” —Sunday Times”Who We Are and How We Got Here provides a marvellous synthesis of the field.” —Financial Times About the Author DAVID REICH, Professor of Genetics at Harvard Medical School, and a Howard Hughes Medical Institute Investigator, is one of the world’s leading pioneers in analyzing ancient human DNA. In a 2015 article in Nature, he was named one of ten people who matter in all of the sciences for his contribution to transforming ancient DNA data “from niche pursuit to industrial process.” Awards he has received include the Newcomb Cleveland Prize from the American Association for the Advancement of Science and the Dan David Prize in the Archaeological and Natural Sciences for his computational discovery of intermixing between Neanderthals and Homo sapiens. Excerpt. © Reprinted by permission. All rights reserved. Part IThe Deep History of Our Species1How the Genome Explains Who We AreThe Master Chronicle of Human VariationTo understand why genetics is able to shed light on the human past, it is necessary to understand how the genome—defined as the full set of genetic code each of us inherits from our parents—records information. James Watson, Francis Crick, Rosalind Franklin, and Maurice Wilkins showed in 1953 that the genome is written out in twin chains of about three billion chemical building blocks (six billion in all) that can be thought of as the letters of an alphabet: A (adenine), C (cytosine), G (guanine), and T (thymine).1 What we call a “gene” consists of tiny fragments of these chains, typically around one thousand letters long, which are used as templates to assemble the proteins that do most of the work in cells. In between the genes is noncoding DNA, sometimes referred to as “junk” DNA. The order of the letters can be read by machines that perform chemical reactions on fragments of DNA, releasing flashes of light as the reactions pass along the length of the DNA sequence. The reactions emit a different color for each of the letters A, C, G, and T, so that the sequence of letters can be scanned into a computer by a camera.Although the great majority of scientists are focused on the biological information that is contained within the genes, there are also occasional differences between DNA sequences. These differences are due to random errors in copying of genomes (known as mutations) that occurred at some point in the past. It is these differences, occurring about one every thousand letters or so in both genes and in “junk,” that geneticists study to learn about the past. Over the approximately three billion letters, there are typically around three million differences between unrelated genomes. The higher the density of differences separating two genomes on any segment, the longer it has been since the segments shared a common ancestor as the mutations accumulate at a more or less constant rate over time. So the density of differences provides a biological stopwatch, a record of how long it has been since key events occurred in the past.The first startling application of genetics to the study of the past involved mitochondrial DNA. This is a tiny portion of the genome—only approximately 1/200,000th of it—which is passed down along the maternal line from mother to daughter to granddaughter. In 1987, Allan Wilson and his colleagues sequenced a few hundred letters of mitochondrial DNA from diverse people around the world. By comparing the mutations that were different among these sequences, he and his colleagues were able to reconstruct a family tree of maternal relationships. What they found is that the deepest branch of the tree—the branch that left the main trunk earliest—is found today only in people of sub-Saharan African ancestry, suggesting that the ancestors of modern humans lived in Africa. In contrast, all non-Africans today descend from a later branch of the tree.2 This finding became an important part of the triumphant synthesis of archaeological and genetic and skeletal evidence that emerged in the 1980s and 1990s for the theory that modern humans descend from ancestors who lived in the last hundred thousand years or so in Africa. Based on the rate at which mutations are known to accumulate, Wilson and his colleagues estimated that the most recent African ancestor of all the branches, “Mitochondrial Eve,” lived sometime after 200,000 years ago.3 The best current estimate is around 160,000 years ago, although it is important to realize that like most genetic dates, this one is imprecise because of uncertainty about the true rate at which human mutations occur.4The finding of such a recent common ancestor was exciting because it refuted the “multiregional hypothesis,” according to which present-day humans living in many parts of Africa and Eurasia descend substantially from an early dispersal (at least 1.8 million years ago) of Homo erectus, a species that made crude stone tools and had brains about two-thirds the size of ours. The multiregional hypothesis implied that descendants of Homo erectus evolved in parallel across Africa and Eurasia to give rise to the populations who live in the same places today. The multiregional hypothesis would therefore predict that there would be mitochondrial DNA sequences among present-day people that are separated by more than a million years, the age of the dispersal of Homo erectus and its descendants. However, the genetic data was impossible to reconcile with this prediction. The fact that all people today share a common mitochondrial DNA ancestor about ten times more recently showed that humans today largely descend from a much later expansion from Africa.Anthropological evidence pointed to a likely scenario for what occurred. The earliest human skeletons with “anatomically modern” features—defined as falling within the range of variation of all humans today with regard to having a globular brain case and other traits—date up to around three hundred thousand years ago and are all from Africa.5 Outside of Africa and the Near East, though, there is no convincing evidence of anatomically modern humans older than a hundred thousand years ago and very limited evidence more than fifty thousand years ago.6 Archaeological evidence of stone tool types also points to a great change after fifty thousand years ago, a period known to archaeologists of West Eurasia as the Upper Paleolithic, and to archaeologists of Africa as the Later Stone Age. After this time, the manufacture of stone tools became far more efficient, and there were changes in style every few thousand years, compared to the glacial earlier pace of change. Humans in this period also began to leave behind far more artifacts that revealed their aesthetic and spiritual lives: beads made of ostrich eggshells, polished stone bracelets, body paint made from red iron oxide, and the world’s first representational art. The world’s earliest known figurine is a roughly forty-thousand-year-old “lion-man” carved from a woolly mammoth tusk, found in Hohlenstein-Stadel in Germany.7 The approximately thirty-thousand-year-old drawings of pre–ice age beasts, found on the walls of Chauvet Cave in France, even today are recognizable as transcendent art.The dramatic acceleration of change in the archaeological record after around fifty thousand years ago was also reflected by evidence of population change. The Neanderthals, who had evolved in Europe by around four hundred thousand years ago and are considered “archaic” in the sense that their body shape did not fall within present-day variation, went extinct in their last holdout of western Europe between about forty-one thousand and thirty-nine thousand years ago, within a few thousand years of the arrival of modern humans.8 Population turnovers also occurred elsewhere in Eurasia, as well as in southern Africa, where there is evidence of abandonment of sites and the sudden appearance of Later Stone Age cultures.9The natural explanation for all these changes was the spread of an anatomically modern human population whose ancestors included “Mitochondrial Eve,” who practiced a sophisticated new culture, and who largely replaced the people who lived in each place before.The Siren Call of the Genetic SwitchThe finding that genetics could help to distinguish between competing hypotheses of human origins led in the 1980s and 1990s to exuberance about the power of the discipline to provide simple explanations. Some even wondered if genetics might be able to do more than provide a supporting line of evidence for the spread of modern humans from Africa and the Near East after around fifty thousand years ago. Perhaps genes could also be the cause of that spread, offering an explanation as simple and beautiful as the four-letter code written in DNA for the quickening pace of change in the archaeological record.The anthropologist best known for embracing the idea that a genetic change might explain how we came to be behaviorally distinct from our predecessors was Richard Klein. He put forward the idea that the Later Stone Age revolution of Africa and the Upper Paleolithic revolution of western Eurasia, when recognizably modern human behavior burst into full flower after about fifty thousand years ago, were driven by the rise in frequency of a single mutation of a gene affecting the biology of the brain, which permitted the manufacture of innovative tools and the development of complex behavior.According to Klein’s theory, the rise in frequency of this mutation primed humans for some enabling trait, such as the ability to use conceptual language. Klein thought that prior to the occurrence of this mutation, humans were incapable of modern behaviors. Supporting his notion are examples among other species of a small number of genetic changes that have effected major adaptations, such as the five changes that are sufficient to turn the tiny ears of the Mexican wild grass teosinte into the huge cobs of corn that we buy in the supermarket today.10Klein’s hypothesis came under intense criticism almost as soon as he suggested it, most notably from the archaeologists Sally McBrearty and Alison Brooks, who showed that almost every trait that Klein considered to be a hallmark of distinctly modern human behavior was evident in the African and Near Eastern archaeological records tens of thousands of years before the Upper Paleolithic and Later Stone Age transitions.11 But even if no single behavior was new, Klein had put his finger on something important. The intensification of evidence for modern human behavior after fifty thousand years ago is undeniable, and raises the question of whether biological change contributed to it.One geneticist who came of age at this time of exuberance about the power of genetics to provide simple explanations for great mysteries was Svante Pääbo, who arrived in Allan Wilson’s laboratory just after the “Mitochondrial Eve” discovery, and who would go on to invent much of the toolkit of the ancient DNA revolution and to sequence the Neanderthal genome. In 2002, Pääbo and his colleagues discovered two mutations in the gene FOXP2 that seemed to be candidates for propelling the great changes that occurred after around fifty thousand years ago. The previous year, medical geneticists had identified FOXP2 as a gene that, when mutated, produces an extraordinary syndrome whose sufferers have normal-range cognitive capabilities, but cannot use complex language, including most grammar.12 Pääbo and his colleagues showed that the protein produced by the FOXP2 gene has remained almost identical during the more than hundred million years of evolution separating chimpanzees and mice. However, two changes to the protein occurred on just the human lineage since it branched out of the common ancestral population of humans and chimpanzees, suggesting that the gene had evolved much more rapidly on the human lineage.13 Later work by Pääbo and his colleagues found that engineered mice with the human versions of FOXP2 are identical to regular mice in most respects, but squeak differently, consistent with the idea that these changes affect the formation of sounds.14 These two mutations at FOXP2 cannot have contributed to the changes after fifty thousand years ago, since Neanderthals shared them,15 but Pääbo and his colleagues later identified a third mutation that is found in almost all present-day humans and that affects when and in what cells FOXP2 gets turned into protein. This change is absent in Neanderthals, and thus is a candidate for contributing to the evolution of modern humans after their separation from Neanderthals hundreds of thousands of years ago.16Regardless of how important FOXP2 itself is in modern human biology, Pääbo cites the search for the genetic basis for modern human behavior as a justification for sequencing the genomes of archaic humans.17 Between 2010 and 2013, when he led a series of studies that published whole-genome sequences from archaic humans like Neanderthals, Pääbo’s papers highlighted an evolving list of about one hundred thousand places in the genome where nearly all present-day humans carry genetic changes that are absent in Neanderthals.18 There are surely biologically important changes hiding in the list, but we are still only at the very beginning of the process of determining what they are, reflecting a more general problem that we are like kindergartners in our ability to read the genome. While we have learned to decode the individual words—as we know how the sequence of DNA letters gets turned into proteins—we still can’t parse the sentences. The sad truth is that it is possible to count on the fingers of two hands the examples like FOXP2 of mutations that increased in frequency in modern humans under the pressure of natural selection and whose functions we partly understand. In each of these cases, the insights only came from years of hand-to-hand combat with life’s secrets by graduate students or postdoctoral scientists making engineered mice or fish, suggesting that it will take an evolutionary Manhattan Project to understand the function of each mutation that we have and that Neanderthals do not. This Manhattan Project of human evolutionary biology is one to which we as a species should commit ourselves. But even when it is carried out, I expect that the findings will be so complicated—with so many individual genetic changes contributing to what makes humans distinctive—that few people will find the answer comprehensible. While the scientific question is profoundly important, I expect that no intellectually elegant and emotionally satisfying molecular explanation for behavioral modernity will ever be found.But even if studying just a few locations in the genome will not provide a satisfying explanation for how modern human behavior evolved, the great surprise of the genome revolution is the explanations it is starting to provide from another perspective—that of history. By comprehending the entire genome—by going beyond the tiny slice of the past sampled by our mitochondrial DNA and Y chromosome and embracing the story of our past told by the multiplicity of our ancestors that is written in the record of our whole genome—we have already begun to sketch out a new picture of how we got to be the way we are. This explanation based on migrations and population mixture is the subject of this book. Read more

Reviews from Amazon users which were colected at the time this book was published on the website:

⭐The message of Who We Are and How We Got Here, by David Reich, is that we are the descendants of men who killed their enemies and took their land. That is how we got here. Sometimes our ancestors kept the females of their enemies as concubines. Sometimes they annihilated them too.Because I am a kind hearted guy I do not like thinking that my ancestors would do that. I never would. I am sure Dad never did. Unfortunately, we cannot choose our ancestors. We cannot improve their behavior.The big picture about human evolution is that it began in Africa about six million years ago when the Rift Valley developed, splitting the common ancestor of humans and chimpanzees. The chimps got the better half of the deal. Chimps like to eat leaves and fruit. They found these abundantly in the jungle areas they lived in. Our ancestors had to hustle to survive. The half they got dried up into areas that are grasslands to this day in eastern Africa.The first distinctly human characteristic that evolved was the human foot and the ability to walk upright. Chimpanzee feet resemble their hands. They can manipulate objects with their feet. We cannot. They cannot walk upright for long distances.After our ancestors evolved the ability to walk upright their brains began to grow, indicating the evolution of more intelligence. They could not run fast enough to catch the game animals they learned to eat. They could not outrun the carnivorous animals for whom they were game. They also lacked long and sharp teeth and claws. They had to learn how to use sticks and rocks as weapons. Eventually these became stone tipped spears and hatchets.From time to time, beginning about 2.8 million years ago, a small number of humans left Africa, and spread. Nevertheless, human evolution was moving faster in Africa for two reasons. First, the number of humans in Africa was far greater than the number of humans out of Africa. Large populations usually evolve faster than small populations, because there is more scope for beneficial mutations to develop and spread.Second, the inhabitants of Africa had more genetic diversity. This is a characteristic Negroes retain to the present. More genetic diversity enables a population to evolve faster in any direction. The alleles it needs are already present. An allele is a variation of a gene.When the next small group of humans left Africa it encountered the descendants of the previous group. Because it had evolved more intelligence it “displaced” (i.e., annihilated) the previous group. It was able to do so because it had evolved more intelligence. Nevertheless, some interbreeding occurred.In recent years scientists have developed the ability to trace the migrations, mergers, and displacements of prehistoric humans by studying DNA from living humans and the remains of prehistoric humans. David Reich is a professor at Harvard, and a pioneer in this field.About four to six hundred thousand years ago the ancestors of Neanderthals left Africa, and populated the Near East and Europe, where they continued to evolve. Meanwhile modern humans appeared in Africa slightly more than 100,000 years ago. These modern humans had physical dimensions that correspond to the physical dimensions of contemporary humans. The archaic humans did not. About 50,000 years ago one hundred to several hundred of these modern humans left Africa. About 35,000 years ago these modern humans, who for over a century have been called “Cro Magnons,” entered Europe. In several thousand years they displaced the Neanderthals. Again, there was some interbreeding.About 8,000 years ago the displacers were displaced by Neolithic farmers spreading out from the near east, where farming originated.Here I must tepidly disagree with the distinguished Harvard professor. He claims that the Paleolithic hunters the Neolithic farmers found in Europe had blue eyes, and dark skin.Although blue eyes are sometimes found in Caucasians, they are rare in the entire human species. I cannot understand what population pressures would have caused all of the Paleolithic hunters, whose ancestors had displaced the Neanderthals, to develop blue eyes.Here I agree with Utah University Professors Gregory Cochran and Henry Harpending who wrote in The 10,000 Year Explosion: How Civilization Accelerated Human Evolution, that blue eyes developed from a single mutation in a single European about 6,000 to 10,000 years ago. Cochran and Harpending speculate that blue eyes spread because people with blue eyes were considered to be more attractive, so they had an easier time finding mates.https://www.amazon.com/gp/customer-reviews/R1QW7U2G2GJTXC?ref=pf_ov_at_pdctrvw_srpCochran and Harpending do consider the possibility that the hunters of Europe had dark skin. They reason that dark skinned hunters would not get rickets, because fresh meat is rich in vitamin D. It was only with the use of agriculture – which reduced the consumption of fresh meat – in northern climates that skin became lighter to use the sun to develop vitamin D.This is an interesting theory, but for two problems. First, with the exception the liver of certain mammals, fresh meat is not a natural source of vitamin D. Second, there is no reason to believe that the ancestors of the Eskimos ever practiced agriculture. Nevertheless, they have light skin.So, again I disagree with the Harvard professor. This disagreement is important, because Professor Reich claims that the genetic differences between the Paleolithic hunters and the Neolithic farmers who displaced them were as different as between contemporary Europeans and Han Chinese. I think they were both recognizably Caucasian. This is an issue that will be resolved as more is leaned from DNA analysis.We do not need to guess about the race of the Neolithic farmers. Their descendants continue to live on the Mediterranean island of Sardinia in a genetically undiluted form. They resemble Italians and Greeks.Nevertheless in the rest of Europe they were displaced (again I mean “annihilated”) by herding people from the Russian steppes north of the Black Sea and the Caspian Sea. These were the people – and here I agree with Professor Reich – who settled Europe, Iran, and India, spreading Indo European languages.The advantages these pastoral people had over the Neolithic farmers were the facts that they had domesticated the horse, and invented the wheel and wheeled wagons. These gave them greater mobility. They may also have carried an ancestor of bubonic plague, to which they had resistance, while the Neolithic farmers did not.At any rate, these herders from the Russian steppes were not displaced. Their descendants still live there. Comparing them with the inhabitants of Sardinia we can see that they both belong to the Caucasian race, although Professor Reich is uncomfortable with the use of the word “race.” That discomfort is the reason I give this fascinating book a four star rating, rather than a five star rating.Professor Reich tries to straddle the divide between those who claim, “Race is only a social construct,” and those who claim that the white race is superior to the other races. By “white” those in the second group exclude non European Caucasians, and even Ashkenazi Jews, although the Ashkenazim have lived in Europe for about two thousand years.To the first group he says with more hesitation than I have when disagreeing with him, “the orthodoxy that has emerged over the last century – the idea that human populations are all too closely related to each other for there to be substantial average biological differences between them – is no longer sustainable.”To the second group he claims that what are considered to be the three main races of Caucasians, Mongloids, and Negroes are did not exist until more than about 10,000 years ago, but that they are the more recent results of migrations and mixtures.The more plausible theory I have encountered elsewhere – one again based on DNA differences – is that the difference between Negroes and everyone else is about 50,000 years old, and that the split between Caucasians and Mongoloids happened about thirty thousand years ago.In the third part of his book Professor Reich makes assertions, which I suspect were motivated more by a desire to maintain harmonious relationships with other Harvard professors than by a desire to follow the facts wherever they lead. For example, he calls Professors Cochran, Harpending, Nicholas Wade, the author of A Troublesome Inheritance: Genes, Race, and Human History,https://www.amazon.com/gp/customer-reviews/RS1CNJ677HVQB?ref=pf_ov_at_pdctrvw_srpand Nobel Laureate James Watson “racists” for their willingness to go further than he is in making assertions about human genetics that are either known or highly probable.Oh well. It is Professor Reich’s life, his academic career, and his position on invite lists to fashionable dinner parties. He has written a fascinating book.I look forward to the day when he and other geneticists have less reason to fear the constraints of political correctness.

⭐Reich is a geneticist at Harvard’s Medical School. Recent advances in DNA sequencing have made it possible to extract sequences from humans who lived tens of thousands of years ago. Those ancient human remains can help explain who we are and where we came from. DNA can reveal something of human population migrations over time. It also tells us that Europeans are a mixture of ancient peoples. Reich has tried to make the book accessible to non-experts, but it is not an easy read. However, it is worth the effort because it contains fascinating information about our past.Modern people are often unrelated to the people who lived in the same area in the past. The ancestors of the modern British arrived 4,400 years ago and replaced the people who built Stonehenge. The Bell Beaker people (named after their pots) traveled to Britain and replaced 90% of the indigenous population. Similar migrations and population mixtures characterize human prehistory on all continents. Ancient DNA teaches us that the population in any one place has often changed many times since the great human post-ice age expansion. Once invaders moved into an area, they have tended to kill off the men and breed with the local women. The mixing of peoples has been commonplace and Europeans are essentially mongrels.Homer described societies in which warlords gained prestige and wealth through plunder and rape. It is similar to what we now know of the Yamnaya (the Beaker people represented the far western wave of Yamnaya migrations). Of theirs and other such male-dominant migrations, Reich comments: “Males from populations with more power tend to pair with females from populations with less.”Modern humans emerged out of Africa 50,000 years ago. Our species is alone today, but we used to share the planet with other human species, like Neanderthals and Denisovans. We interbred with Neanderthals about 50,000 years ago. As a result, Europeans are about 2% Neanderthal. Within a few thousand years, the Neanderthals were extinct. Given our track record, our ancestors probably had something to do with it.Farming was invented in the Near East 11-12,000 years ago. Ten thousand years ago Europeans were a mixture of four main groups: Iranian farmers, Levant farmers, western hunter-gatherers, and eastern hunter-gatherers. The four population groups mixed together in different proportions in different countries. Europe was later transformed by two great migrations. The first was 8500 years ago and involved near eastern farmers. Farmers arrived from Anatolia (modern Turkey) and mixed with the local populations, this is the largest source of ancestry in Europeans today. A second, later migration came from the Eurasian Steppe. The Steppe includes the grass plains bordering the Black and Caspian seas. “People [from the Steppes] took advantage of two powerful inventions: the wheel and the domestication of the horse,” said Reich. “They were able to exploit the grasslands of the Steppes in a way that hadn’t been done before.”In 1786, Sir William Jones a Briton living in Calcutta discovered that Sanskrit and ancient Greek were related languages. Indo-European languages are all very similar. Latin, Greek, and Sanskrit have common words for wheels, horses, and carts. This led to the recognition of the vast Indo-European language family – which includes the Germanic, Celtic, Italic, near eastern (Iranian), and north Indian languages (Hindi, Urdu, Bengali, Punjabi, Marathi, etc). Until recently there was no consensus on how this might have occurred. Reich has now shown that the Indo-European languages and the largest single component of the genetic makeup of Europe and North India today stem from the Steppe migrations around 4,500 ago. Most people of European descent have close genetic and linguistic ties with near eastern and north Indian peoples.The ancestors of East Asians, Europeans, West Africans, and Australians were, until recently, almost completely isolated from one another for 40,000 years or longer, which is more than sufficient time for the forces of Darwinian evolution to work. Reich found himself criticized after publishing an Op-Ed in the New York Times in 2018, based on this book. He claimed that ancient DNA reveals “hard evidence of substantial differences across populations.” Reich claimed that because of political correctness scientists are unwilling to do research on genetic variation between human populations, despite the fact that genetic variations do exist. “It is simply no longer possible to ignore average genetic differences among ‘races,’” he wrote.The recent Coronavirus pandemic has illustrated that susceptibility to particular diseases may differ among different populations. There have been calls for the higher mortality rates among African-Americans to be investigated. We know that genetic factors help explain why multiple sclerosis is more common in European-Americans than in African-Americans, and why the reverse is true for end-stage kidney disease. We also know that genetics probably explains why northern Europeans are taller on average than southern Europeans. Reich argues that if scientists in the West don’t investigate these differences the Chinese will. However, many people in the West remember the horrors of Nazi Germany and the way eugenics was used to justify the regime’s atrocities. Academics are probably wary about emphasizing racial differences because of the way science was misused in the past.Some readers from countries that take their origin myths seriously may find Reich’s conclusions unpalatable. Reich’s Indian collaborators did not like hearing that their own DNA samples attested to massive past migrations into the Indian subcontinent. The Japanese may not like that they share 80 percent of their DNA with Koreans. This is a fascinating book that changes the way we should think about our past.

⭐The author is certainly an expert in genetics, and particularly in the study of ancient human DNA. Whilst this is attempt to write for both the expert and the general reader with an interest in human origins and our dispersal around the globe, I felt that it is closer to an academic than to a general audience and readership, even for those interested in science and usually able to follow the material. For me it was hard to follow at times, probably because the writing style is rather dry for such a fascinating subject, and i found it all rather a struggle to finish. That may well say more about my attention span (maybe i was expecting more geography and less detailed DNA) than about the quality of the science or even the writing but – no mistake this book is far from easily read or followed

⭐The book proved to be a difficult read for me. This emanated from the intrinsic complexity of comparing ancient and modern genomes of populations continuously migrating and interbreeding. The populations in a place today are never the direct descendants of the people that lived in the same place in the past but the result of continuous migrations and interbreeding as complex in the past as in the present. At times I felt lost. Moreover, I felt that the narrative was addressed to a more specialist audience than the general reader and this was corroborated by specialist statistics used such as the four population test which must be known only to specialists studying ancient genomes.The book presents novel findings but it is also a work in progress in that it is anticipated that in the coming decade more ancient genomes will be sequenced but also more sophisticated statistic techniques will be developed and employed.The determination of ancient genomes became possible because since the sequencing of the human genome project in 2006, the methods became thousands of times more efficient and thousands of times less expensive. Whole genomes provide much more information than the previously used sequencing of the male (Y) chromosome DNA and mitochondrial DNA which is exclusively inherited by the females.Comparisons of genomes, ancient and modern is based on the determination of mutations over time while their rate is constant in time. Particularly important are single letter mutations known as Single Nucleotide Polymorphism (SNP) of which there are literally thousand in the genome.The study of ancient genomes revealed that there was interbreeding of both Neanderthals and Denisovans with modern human populations.Even before reading the book, I had known that there is no genetic basis for racism in that the genetic variation within Africa is higher than between a non -African and an African.On the other hand, I obtained interesting information on inequality, not inequality between male and female but the inequality of access of a privileged male individual or group to females. In this regard the result of genomic studies of interbreeding between Americans of West European and West African origin revealed the dominance of American males of West European origin breeding with American females of Wets African origin.On a similar vein was the study of Y chromosomes which suggested that one single male who lived around the time of the Mongols left many millions of direct male-line descendants across the territory that the Mongols occupied. The evidence is that about 8 percent of males in the lands that the Mongol Empire once occupied share a characteristic Y-chromosome sequence or one differing just a few mutations. This Y-chromosome was called ‘Star Cluster’to reflect the idea of a single ancestor with many descendants; and estimated the date of the founder of this lineage to be thirteen hundred to seven hundred years ago based on the estimated rate of accumulation of mutations on the Y chromosome. The date coincides with that of Genghis Khan, suggesting that this single successful Y chromosome may have been his.The inbreeding of Ashkenazi Jews to which the author belongs is a well known fact. What was new and surprising to me was that endogamy is widely practiced in India, a nation in excess of one billion inhabitants. This is due to the caste system numbering thousands of sub-groups in which endogamy is practiced. The study of such groups is important for the cure and prevention of genetic diseases emanating from inbreeding.Ancient human genomes are often contaminated by genomes of pathogens which renders the identification of human genomes difficult. On the other hand the identification of the genomes of these pathogens sheds light on the diseases with which these people were afflicted. Particularly important in this regard was the identification of ‘Yersinia pestis’, the bacterium responsible for the black death, estimated to have wiped out one-third of the population of Europe, India and China seven hundred years ago.

⭐David Reich is one of the leading population geneticists alive, and this book is about how DNA evidence helps us understand the relationships between population groups. When and which people migrated into Europe? Where do the the people of Papua New Guinea come from? Genetic differences between peoples help us answer such questions… and many more.This book contains good explanations of which techniques are used to analyze population genetics. Why these methods work and what their limitations are is discussed. Of course, the most important topic is the findings of these methods. DNA analysis has in many cases confirmed things we already knew from other types of evidence; archeology and fossil evidence and such. However, in many cases, the science of DNA analysis has forced us to reinterpret what we thought we knew. This is the power of genetics; it can be analyzed to get us one step closer to understanding what humans are.Genetics has a controversial history, obviously. Yet, I still find his need for ‘justifying’ doing research in genetics a pity. As people of science, we should know what’s true whether we like the truth or not. He agrees, but unfortunately in his desire to appear non-racist he throws good scientists under the bus. Some are bad and his harsh criticism is justified, sure, but some of the people criticized simply had totally reasonable scientific questions. This is my only substantial criticism of the book.The science and technology of DNA analysis is progressing at an amazing rate. It will help us answer all kinds of questions. It will be used in medicine, to understand psychological differences between humans, and much, much more. As the science progresses, many things we think we know will be questioned.Despite my one criticism, the book in general is amazing. This is simply *the* book to read if you’re interested in human origins, human differences and similarities, or simply if you’re interested in where you come from. This book gives the current best scientific understanding of Who We Are and Where We Come From.

⭐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.

⭐Despite being something who is usually at ease with scientific books intended for the non-scientist and this was a subject in which I am very interested, I’m afraid I found ‘Who we are’ impossible to understand and abandoned the effort after the first 40 pages or so. A real disappointment. A decent editor might have helped reduce the jargon, the rambling, the inconsequentials. And I had deliberately chosen the print rather than the Kindle version because I realized that it might be difficult read.

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