PQC: Sorry folks, I forgot to “CHAPTER” the post!

Roots:  What race means now in the light of new scientific research


            When she was growing up, my little sister was a diehard fan of Morrissey, the frontman for the Smiths, hailed as a genius songwriter and British cultural icon. For one of a handful of brown girls in a white working-class Southeast London suburb, indie music spoke to that cold, lonely feeling of not quite being able to fit in. If the far-right British National Party was marching outside our door, its members calling for an all-white nation with no immigrants, inside her headphones was a different British voice that she could relate to. He was a refuge from those who insisted that we all had to be the same.

            But in an interview with a music magazine in 2007, Morrissey said something that couldn’t help but trouble my sister, as well as other fans. “Whatever England is now, it’s not what it was and it’s lamentable that we’ve lost so much,” he complained. He railed against high immigration, against what he saw as a change in the character of Britain. There was public outrage. She lost a hero. But as we in our family knew too well, out in the country as a whole there were many who felt this way. This was a debate that had been simmering for decades, occasionally stoked by national politics, making people anxious, wondering what it meant to be British.

            A decade later, the pot bubbled over. A financial crisis and economic austerity, coupled with higher-than-usual rates of immigration from eastern Europe, helped fuel support for nationalists who wanted to cut the country free from the European continent. In a referendum in 2016, the majority of voters agreed that leaving the European Union might be a good plan. They were promised a new dawn. The nation would stand alone, the way it had done during the days of empire, riding the waves of unbridled trade and setting its own rules on who would be allowed into the country.

            For visible immigrants, or children of immigrants like my sisters and me, watching this play out could sometimes feel like an out-of-body experience. The borough in which my parents lived and where we grew up was one of only five out of the thirty-two in London that voted to leave. As citizens we had the right to vote to decide Britain’s future, but we also knew that a sizable slice of other voters wanted fewer of us there in the first place. A campaign poster showed legions of men with skin as brown as ours queuing up in front of the slogan “Breaking Point.” The far right was emboldened. Around the time of the referendum, reports of race-based crime rose, and there was a sharp spike in the kind of everyday racism that I had last seen as a teenager.

            Squaring your appearance with your nationality is one of the hardest parts about being a member of an ethnic minority. Not all, but some of those who voted to leave Europe wanted a return to their own particular vision of Britain. Skin color mattered to them because skin color—white skin—was a visible baseline, a reference point. White was how the British had always looked, from the beginning, before empire, before Shakespeare, before kings and queens, before culture and values. Britain, as far as we were aware, has been forever white. In their eyes my failure to be the right color truly undercut my claim to Britishness.

            Nobody could have predicted then that, by an almost cosmic coincidence, at the very moment Britons were struggling to define their identity in the face of political turmoil, and particularly for those racists who saw Britain as a white nation first and foremost, some news was coming. They were about to be thrown a curve ball.

            I saw it for myself at London’s Natural History Museum in early 2018, a package no fancier than a bunch of old bones.

            The skeleton is laid out neatly in a small corner of the museum. Most of the visitors don’t linger as I do. To be honest, it looks unremarkable. But this is the frame of one of the oldest dead bodies ever found in the country, some ten thousand years old. And it’s full of secrets. Almost as soon as the bones were discovered in caves in Cheddar Gorge in Somerset in 1903, giving their owner the name Cheddar Man, people began to wonder how this individual must have looked. They wanted to put a face to one of our early ancestors. Archaeologists could certainly guess that he was slightly short by modern standards, that he probably had a good diet, and that he may have been around twenty years old when he died. One speculative reconstruction showed him to be white-skinned, with rosy cheeks and a trailing brown mustache. But his actual appearance was a mystery.

            This is where the genetic study of the bones of our distant ancestors, of their ancient DNA, came in. It has achieved what the Human Genome Diversity Project couldn’t. The DNA of living people offers a limited and fuzzy picture of the past. When it comes to tracking human migration patterns over thousands of years, even archaeology and linguistics can’t provide all the detail that ancient DNA can. By around 2010 genetic sequencing techniques had developed far enough to tease out highly reliable samples of DNA from ancient specimens (a bone just behind the ear turned out to be best) and use them to help reconstruct entire genomes of long-dead people. The use of this technique has mushroomed in the last decade. It has been credited with solving historical mysteries at a stroke. Thousands of skeletons from all over the world have been analyzed already, and as the British public were about to learn in early 2018, Cheddar Man was one of them.

            Scientists at the Natural History Museum and University College London revealed that Cheddar Man probably had blue eyes and curly hair—no great surprise here. But what came as a real shock to many Britons was that his bones also carried genetic signatures of skin pigmentation more commonly found in sub-Saharan Africa. It was probable that Cheddar Man had dark skin. So dark, in fact, that by today’s standards he would be considered black. The revelation, along with a dramatic new reconstruction of his face markedly different from the original one, made front-page news and television bulletins:

            “Hard Cheese for the Racist Morons,” ran a headline in the tabloid Mirror.

            “Another Racial Panic for White Supremacists,” announced the news website Salon.

            Panic was indeed sparked. There were all the stages of grief. On far-right websites, a few immediately began doubting the scientific results—maybe, just maybe, the researchers had gotten it wrong. Some hopefully voiced the possibility that Cheddar Man hadn’t been an actual Briton at all, but was just a passing visitor who happened to die here, like an unlucky tourist. Finally, there was acceptance. Some, especially those who for so long had believed that skin color was the basic measure of Britishness, wondered if perhaps it was time to rethink national identity.

            If the original Britons were black, all bets were off.

            Throughout the frenzy, there was one set of people for whom the news barely registered a flicker on their excitement dial. They weren’t shocked at all.

            “With the whole Cheddar Man thing, I was amazed initially at just how much press coverage it got,” I’m told by Mark Thomas, of University College London, who worked on the finding. Leaning back in his chair casually, wearing stonewashed jeans and a granddad-collar shirt, Thomas is about as relatable as professors come. He is one of the world’s leading experts on ancient DNA, and from this position of authority he has a tendency to tell it how it is. For geneticists like him, the Cheddar Man discovery was unremarkable given what they already knew. They had more or less expected it.

            Thomas had welcomed the discovery as just another piece of evidence in a huge body of research. It was a couple of sentences in his latest paper. Scientists had already known for a few years, from analyzing the skeletons of other hunter-gatherer bones found in western Europe, that dark skin pigmentation could well have been common back then. After all, light skin was likely an evolutionary adaptation, one that helped people living in northern climates absorb more vitamin D because there wasn’t enough sunshine. The first human pioneers probably didn’t arrive in Europe or Asia looking white, because they had originally migrated from Africa, where there was little or no survival advantage in having little skin pigmentation and hence, lighter skin.

            What researchers were a little less sure about was how quickly lighter skin emerged, where and when. “Over the last ten thousand years? Or over the last forty thousand years?” asks Thomas. One theory is that it developed very slowly and gradually over the last roughly forty thousand years, since modern humans started to live in Europe. Another theory is that it was a more recent phenomenon, which came perhaps with the advent of farming. Trading a hunter-gatherer lifestyle for settled agriculture would have limited people’s diets and made it even more vital that they get the vitamin D they needed from the action of sunlight on their skin rather than from their food. Another theory is that light skin emerged elsewhere in the world, outside western Europe, and that the movement of peoples would have then introduced it into the darker-skinned European populations. Evidence as it stands indicates that, like the Cheddar Man, many other pre-farming hunter-gatherers who lived in western Europe during this time and at least up until as recently as seven thousand years ago would have had light eyes, dark hair, and dark skin, and that the first farmers to come into the region later from the east brought with them their lighter skin and brown eyes.

            One thing was clear: Cheddar Man wasn’t an exception in his time. People all over the world then didn’t look anything like the way we look now. Not only this, they looked more different from each other than we do today.

            “Differentiation between groups in different parts of the world would have been greater,” explains Thomas. The scientific explanation for this is genetic drift. Being in small groups as they were, every breakaway bunch of migrants as it moved began to look more and more different from the relatives they left behind as time passed. Since then, as groups grew bigger and remixed with each other, populations across the world have become more homogenized. Ten millennia ago, we would have struggled to identify a person’s geographical origins by modern measures of race and ethnicity. Appearance didn’t map the way it does now, and physical features may have been dramatically different in different regions.

            When Thomas and his team studied the very earliest farmers in the Fertile Crescent, who lived in what is now Iran, and compared them with farmers in nearby Anatolia and the Aegean, they found to their surprise that the two were genetically very distinct from each other. “They were as different as people from Ireland and Thailand today, more or less. I mean, of that order of magnitude.” Today, neighboring populations tend to be much more similar. They’ve mingled and mated with each other, mostly dissolving away the gaps.

            Yet, our modern ideas of race are deeply connected to how we look. Our appearance is a shorthand for the stereotypes, a means of slotting people into groups and making judgments about them. The disbelief that met Cheddar Man’s probable blackness was because many among the British public couldn’t help but assume that Britons had always looked a certain way, even in the distant past. They struggled to categorize Cheddar Man, forgetting that he existed thousands of years before our racial categories came about. He was proof that there couldn’t be anything eternal or pure about race because once upon a time, not so very long ago in evolutionary terms, most of the people on earth didn’t look like us. They were already human. They were, however distantly, us. But they looked different.

            The picture becomes even more complex as we go further back in time. Sarah Tishkoff, a geneticist at the University of Pennsylvania who has led pioneering studies into skin-color variation across Africa, has found that the genetic variants—different forms of the same genes—associated with both dark and light skin have existed in Africa for a long time. The variants that are associated with light skin were common not just in Europe and sometimes in East Asia but also among the San hunter-gatherers. “These are the people in southern Africa who have the oldest genetic lineages in the world,” she says. This suggests that rather than occurring independently outside of Africa as new mutations, gene variants associated with light skin may already have been part of the human genome when people first migrated out of the continent.

            Thus, not only did people with darker-pigmented skin occupy Europe, but even earlier, there were genetic variants for lighter-pigmented skin in Africa. Given the evidence so far, Tishkoff suggests that lighter-pigmented skin may even have been the ancestral state in the long distant past. Underneath their bodies, chimpanzees, our closest genetic relatives, tend to be light skinned, their dark body hair providing protection against the sun. “When our ancestors left the forest and went to the savannah, there would have been selection for better thermoregulation, so getting rid of body hair, increasing the number of sweat glands. And if you’re decreasing the body hair, there would be selection for darker skin.” Darker skin could have been one of the adaptations to a new living environment within Africa.

            When scientific reconstructions are made of earlier human species, such as Homo erectus, they are almost always given dark skin. However, says Tishkoff, “I don’t think that’s necessarily the case, because both light and dark variants have been around for really long time. And there could have been variation in Africa a million, two million years ago.” The long lens of evolutionary history has a way of turning all you think you know on its head.

            Even today, there is far more variation in Africa than the simplistic black-white model of race implies. “I think many people don’t recognize the large range in skin color in Africa,” says Tishkoff. “The whole continent of sub-Saharan Africa is incredibly diverse genetically. It doesn’t fit with a racial model, one homogeneous African race. There’s a huge amount of variation amongst populations in Africa. Skin color is a terrible racial classifier. There really are no good biological classifiers for race.”

            For the biologists who know this, skin color begins to lose its meaning. “I mean, it’s skin pigmentation, you know! It’s just so trivial,” says Mark Thomas, which is why he found reactions to the new finding about the Cheddar Man bizarre. “Obviously there are some idiot racists over there in the corner for which it is important. But I think that if you base your identity on the pigmentation of some West Country bloke from ten thousand years ago then you really should rethink it. My own personal view is that today we over-privilege and fetishize the concept of identity.”

            Thomas reminds me that the physical features we associate with race are poor proxies for overall genetic similarity. Even if one population tends to have darker skin and another lighter, that doesn’t mean their genomes will have less in common than two populations with the same skin color. Variations in physical appearance, whether it be skin pigmentation, ear shape, nose shape, whatever, says Thomas, make the gaps between groups feel far larger than they really are, genetically. Biologically, the differences really are just skin-deep. It’s an error to assume that the internal differences are as profound as the external ones appear. But it’s an easy one to make. “If we could see each other by looking at our genomes, you would be hard pushed to work out whether somebody was from India or from Poland. You’d be hard pushed on the same number of variants,” he explains. “There is relatively little genetic differentiation between Southern India and Ireland. I mean, relatively similar ancestry components. But of course, the pigmentation differences are quite large, and so people assume that these people are massively different genetically.” In that sense, how we look is misleading. “Nature plays dirty tricks on us,” says Thomas.

            It can play tricks on scientists, too. If data seem to suggest that populations are very different, it’s largely because population geneticists are deliberately examining the small sections of our largely shared DNA that happen to differ. This is their job. “We’re zooming in. We’re turning up the contrast on what are actually tiny little differences over extremely closely related populations,” Thomas warns.

            “The past is very surprising,” David Reich, a geneticist in the ancient DNA laboratory at Harvard University, tells me. “It’s different from how most people picture the past in their heads.”

            Reich is the most well-known person in this branch of science, at the forefront of the science of using genetics to plot ancient migrations around the world. At the moment I happen to visit him, though, he has become embroiled in controversy for suggesting in the press that more work needs to be done to understand cognitive and psychological differences between “population groups,” a phrase that most people have interpreted as meaning “racial difference.” His statement—a departure from the nearly seventy-year consensus that studying race isn’t the business of mainstream science—has attracted angry emails from fellow academics. But he hasn’t backed down. When I see him, I expect him to be defensive, maybe even brash.

            I couldn’t be more wrong. With his hands in his lap, so soft-spoken that my voice recorder barely picks up every word, he surprises me with his gentleness. His half of his office is bare, save for a few drawings stuck to the plain white walls. He is unfailingly polite, pausing only to message his wife. The one clue to his global importance as an academic is the steady stream of students and researchers lining up to see him outside. One young man sits with his laptop at a bench in the corridor all day in the hope Reich may be able to spare him a minute or two later on.

            Reich’s lab is a powerhouse. It has scoured the world for skeletons that might provide genetic evidence of the past, and as Reich has noted, it churns out findings so quickly that the amount of data doubles faster than the time it takes to publish new data. Scientific journals simply can’t keep up. But for him, this is more than a scientific gold rush. Genetics has a way of cutting through ancient historical questions in a way that nothing else can. His group, along with the lab of Mark Thomas and others across the world, helped confirm a longtime hypothesis: that farming emerged ten thousand years ago in the Near East—the region between Europe, Africa, and Asia—among genetically varied groups of humans who then helped spread agriculture to other regions. He is also fairly confident that natural selection has caused southern Europeans to be a little shorter on average than northern Europeans—this must have benefited them in some way.

            But it’s the story of migration that is the most revealing. What we think of as “indigenous” Europeans are, Reich and other scientists now understand, the product of a number of migrations over the past fifteen thousand years, including from what is now called the Middle East.

            The British have their own story to tell. “Britons in the past didn’t look like Britons today, and were genetically very unlike Britons today,” Reich says. Whoever the first inhabitants of Britain were, their way of life was likely to have been almost totally replaced around 3,000 to 2,000 BCE by a group of people who traveled through Europe from the steppe grassland that stretches between the Black and the Caspian Seas. They are known by some anthropologists as Beaker folk for their distinctive bell-shaped pottery. Artifacts of Beaker culture are found scattered all over Europe; now, the Harvard team has shown by studying the DNA of four hundred ancient Europeans that these people must have swept in and supplanted almost everyone who was living in Britain at the time as well.

            How they did this is unclear. They could have simply come in large numbers and bred with people who were already there. They may have been better equipped to survive in the environment, through resistance to certain diseases or by virtue of their technology. The preexisting populations could already have been collapsing, as some data suggests. Whatever the explanation, their arrival changed not only the culture but also the way people looked. The steppe people with their Beaker culture also had lighter skin. According to estimates drawn up recently by Reich and his colleagues, this Beaker invasion replaced around 90 percent of Britain’s gene pool in the space of just a few centuries.

            This means that light skin did not define Britons from the beginning. “There’s been a continuous process of skin lightening, with big jumps that occurred at these migrations,” Reich explains. “So, for example, when the first farmers came to Britain about six thousand years ago there is a big change in the average hue of skin around then, predicted by the genetics. And then when these Beaker people spread into Britain, another big jump was associated with that.”

            Some of this work confirms what archaeologists already suspected, but what has been really surprising is just how much churn there has been in global patterns of migration throughout the ages. Reich himself was taught when he was younger that humans spread out of Africa, with little mixing once they started to split off, like branches of a tree. Once they landed somewhere, people stayed put. That was the common assumption. But the evidence that’s now emerging suggests something entirely different. “It became very clear that the big large-scale mixture, migration, or gene flow, however you want to call it, is common and recurrent.”

            The true human story, then, appears to be not of pure races rooted in one place for tens of thousands of years, but of ongoing mixing, with migration constantly changing geographical direction. The cherished belief that people in certain places have looked the same way for millennia has had to give way to the understanding that migration made the world a melting pot long before the last few centuries, long before the multicultural societies we have today. Our roots are not like an orderly family tree but instead are tangled, according to Reich, more like a climbing plant on a trellis. Our ancestors branched out but then came back, and remixed, again and again throughout the past.

            “I think this idea of indigeneity, and you being from a population that has been here for ages—I mean there may be populations that have better claims to that than others—but at some deep level the great majority of people in the world, if not everyone, is not derived directly from people who lived in the same place deep in the past,” he says.

            The British story is just one of thousands. For example, the Beaker folk were part of a far earlier, bigger, and longer migration out of central Eurasia and into many different corners of the world of people associated with what archaeologists call the Yamnaya culture. They were pastoralists, raising and moving livestock, with wagons and horses that made them mobile in a way that may never have been seen before. Their diet was rich in meat and dairy. From roughly seven thousand years ago to roughly five thousand years ago, the Yamnaya (themselves a product of earlier migrations into the region they came from) trekked west and southeast, populating not just Europe but also as far as northern India. They introduced the wheel and, it has been suggested, also cannabis to the regions they migrated to.

            By 3000 BCE, the Neolithic (New Stone Age) farming cultures of Europe had been pretty much replaced. Kumarasamy Thangaraj, at the Centre for Cellular and Molecular Biology in Hyderabad, tells me that around the same time, people of the Yamnaya culture came in from the north of India and mixed with the people who were already there. The Indian population they met was itself a mix of indigenous hunter-gatherers who had originally moved out of Africa many thousands of years earlier and more recent farmers who had migrated from what is now Iran. All Indians, save a tiny community of Andaman Islanders who have been isolated from the Indian mainland for thousands of years, are a blend of these three ancestral populations.

            Confirmed by gene studies, these ancient connections can also be spotted in the words we use. Linguists long ago saw remarkable similarities between European and Indian tongues, describing them together as Indo-European languages. Genetics has added more hard data to the history. Almost all Indians today are genetically closely connected to Europeans by their ancient ancestors who spread the Yamnaya culture, as well as the earlier spread of farmers from the Middle East.

            “If you pay any attention to the discoveries coming out of science, they don’t play into any sort of old systems of prejudice,” David Reich tells me.

            Take Stonehenge, the mysterious prehistoric assembly of standing stones in southwestern England, which attracts more than a million visitors every year. Within a few hundred years of its construction, around five thousand years ago, the Neolithic farmers who had built it were pretty much gone. They were probably replaced by incoming folk who followed the Beaker culture, because Reich’s team couldn’t see much evidence of Neolithic ancestry in the genomes of ancient human remains they were studying that dated from four thousand years ago. Now, just pause to think about what this means: the symbol people associate with ancient Britain, the one thing that couldn’t really be more authentically British, was built by people who are certainly not the main ancestors of those who consider themselves indigenous Britons today.

            Cheddar Man and his relatives, too, who lived ten thousand years ago, couldn’t have been from the same genetic pool as Britons today, because like the builders of Stonehenge, they were replaced by farmers who had spread across Europe from Anatolia. “Cheddar Man and his people formed a unique genetic cluster. They don’t have any direct descendants—only bits of them exist,” explains Mark Thomas. By “bits” he means that Cheddar Man and his relatives who lived on the continent would have bred with whoever came into the region. So although his own particular population and their culture didn’t survive intact, traces of them would have endured, either because they mixed with farmers coming into Britain or because their continental relatives mixed with farmers spreading across Europe. According to Thomas, roughly 10 percent of the ancestry of most modern Britons is shared with Cheddar Man’s genetic group.

            To know that this melting pot has been churning for thousands of years puts a fresh spin on the contemporary idea of race. “I think that genetics and genomics have a wonderful opportunity to undermine these outdated and scientifically unsupported notions of race, ancestry, ethnicity, and identity,” says Thomas. The feeling that there is a “home” for us all, and that our bodies somehow reflect this, deeply and viscerally, begins to melt. The attachments that some people have to places and their relics, the ancient stories they construct around who “our people” were, have to be rethought when they learn that “our people” were actually migrants into a place occupied by others. The relics belong to them. Almost everyone on the planet is the descendant of a migrant from somewhere.

            What is even more mind-bending is that when you look this far back in time, ancestry expands to include almost everyone. “Cheddar Man’s people are to an extent the ancestors of just about everybody in Europe,” he explains. “Indeed, it is possible that in his group are the ancestors of everybody in the world, just about; maybe everybody in the world today.”

            This may seem implausible, but it’s just mathematics. The further back you go in time, the weaker your genetic link to your ancestors. Five generations ago, you would have as many as 32 possible ancestors contributing to your genetic makeup. Nine generations back, you could have 512, many of whom may have contributed next to nothing to your genetic makeup. Zoom back fifteen generations—still just the tiniest slice of recent human history—and you could have 32,768, assuming nobody was having babies with someone they were even distantly related to, which is unlikely. Each of these could give you no more than the tiniest fraction of your DNA. Longer and longer ago, the theoretical number rises into the millions—ultimately, to more people than were even alive at the time. Of course that is impossible. The only explanation is that we are all at least a little inbred.

            Even if you could trace your lineage as far back as Cheddar Man, or even more recently, to Cleopatra, Julius Caesar, or any other figure from antiquity, you would probably be no more related to that individual than is any other person on the street. The more you zoom into the past, the more your ancestral history begins to overlap with that of everyone else on the planet. As Thomas notes, we only have to go back a few thousand years before we reach somebody who is the ancestor of everybody alive today. Go back a few thousand years more, and everybody who was alive is either the ancestor of everybody alive today (if they had descendants who survived), or nobody alive today (if they didn’t). Hence Cheddar Man, if he had children and they had children, and so on until today, is both your relative and mine.

            But what does this have to do with national identity? Many would argue that identity isn’t necessarily about biology or appearance, it’s actually about language, culture, and values. But if it’s about language, culture, and values, then I am as British as anyone. I was born in London, I speak the Queen’s English, and I live a quintessentially English kind of life. My dinners generally comprise roast meat and vegetables (I probably eat a curry as often as most white Britons, and possibly less than some), my radio is set permanently to the BBC, and I celebrate Christmas alongside almost everyone else. If skin color and genetic purity can’t be a measure of ethnic identity, because Britons have changed on both these counts over the millennia, then there’s nothing to prevent anyone from anywhere from earning citizenship and becoming truly British, even by the most conservative standards.

            When considered from the perspective of the deep past, race, nationality, and ethnicity are not what we imagine them to be. They are ephemeral, real only to the extent that we have made them feel real by living in the cultures we do, with the politics we have. David Reich tells me that he draws a sense of global kinship from his work on genetics. “I have a personal way in which genetics is meaningful to me which doesn’t involve my own ancestry,” he says quietly. “I think that one way of relating to the findings about genetics is that we’re all related to each other, and we are all part of a broadly closely related group of people over the last couple of hundred thousand years, with a lot of complexity, and with a lot of mixtures and migrations and reticulations. And we’re all part of that.”

            But then his tone changes. Even after everything he’s said, he doesn’t dismiss the idea of race altogether.

            David Reich isn’t a racist. But neither does he adopt the staunch antiracist position of the old-school population geneticists, such as Luigi Luca Cavalli-Sforza, who bravely debated the scientific racists of their time, who wore their politics on their sleeves. Reich respects Cavalli-Sforza, even writing about how much he has been an inspiration to him. But he confesses that he sees himself as apolitical.

            The genetics of human variation are complicated and subtle, he tells me. And his own position on race is a similarly subtle one. Despite his research revealing the extent of interconnectedness between humans, the great uniting trellis of ancient migration, Reich still suspects there’s something worth investigating about group difference. And he leaves open the possibility that this difference correlates with existing racial categories—categories that many academics would say were socially constructed, and not based in biology at all, except for in very unreliable ways, such as along crude skin-color lines. “There are real ancestry differences across populations that correlate to the social constructions we have,” he tells me firmly. “We have to deal with that.”

            He admits that some categories make no biological sense, such as the way “Latino” is used in the United States to refer to anyone from South America. “‘Latinos’ is a crazy category that encompasses groups with different ancestry mixes ranging from Puerto Ricans, who have very little Native American ancestry, mostly African, a little European; to Mexicans, who have very little African ancestry and [are] mostly Native American, European. . . . It’s a crazy category.” At the same time he thinks some categories may have more biological meaning to them. Black Americans are mostly West African in ancestry and white Americans tend to be European, both correlating to genuine population groups that were once separated at least partially for seventy thousand years in human history. “There’s a long time separating these two groups,” Reich says. “Enough time for evolution to accumulate differences. We don’t know very much about what those differences are because we’re still at the beginning of collectively trying to identify biologically what differences do.”

            He suggests that there may be more than superficial average differences between black and white Americans, possibly even cognitive and psychological ones, because before they arrived in the United States, these population groups had this seventy thousand years apart during which they adapted to their own different environments. Reich implies that natural selection may have acted on them differently within this timescale to produce changes that go further than skin deep. He adds, judiciously, that he doesn’t think these differences will be large—only a fraction as big as the variation between individuals, just as biologist Richard Lewontin estimated in 1972. But he doesn’t expect them to be nonexistent either: as individuals we are so very different from one another that even a fraction of a difference between groups is something.

            They are words I never expected to hear from a respected mainstream geneticist. I know that Reich is not a racist. Indeed, like Cavalli-Sforza, he believes that if race research is done, it will only further demolish old prejudices. Scientists are concerned with fact, not fiction, his argument goes, and the facts we have accumulated so far are simply not in the racists’ favor. The more good work we have, the more it demolishes longstanding racial stereotypes, so there should be no barriers to doing even more research, even if it feels risky. Reich tells me, “My feeling about this field has been that, broadly, it makes telling falsehoods more difficult. That’s my feeling. It may be self-serving, but that’s my feeling. And so I think these surprises, such as ancient Britons were very much more dark skinned than present people, . . . I think this is broadly a force for combating prejudice, because it doesn’t conform to anybody’s pictures they had before.”

            Though Reich sees the racists as factually wrong, he also sees some antiracists—those who insist that we are all exactly the same underneath—as not having the full facts either. “It’s a little bit painful to see very well-meaning people saying things that are contradicted by the science, because we want well-meaning people to say things that are correct,” he says. “The way I see what’s going on in this world right now, there are racist people that are just perpetrating falsehoods, and just representing the science in incorrect ways, tendentious ways in order to achieve certain goals. And then there’s people whose perspective on the world I agree with who are actually saying things that are technically incorrect.”

            Reich is technically correct that there could be more profound genetic differences between population groups than we are aware of at the moment. But to date, no scientific research has been able to show any average genetic differences between population groups that go further than the superficial, such as skin color, or that are linked to hard survival, such as those that prevent a geographically linked disease. There is no variant of any gene that has been found to exist in everyone of one “race” and not in another.

            In London, Mark Thomas, who has collaborated with Reich, remains dismissive of the idea that race as a concept is useful to the study of genetics. “Most researchers, including geneticists, agree that ‘race’ is a socially constructed category. There is no categorical imperative in biology, and no need or value in placing people in biological boxes. There are subtle genetic correlations with geographic origin, and physical traits, as well as medical ones, and understanding those correlations is important. But there are no hard borders, just gentle gradients,” he tells me. “Unfortunately, that doesn’t stop people ‘racializing’ others, and perhaps that reflects our desire to categorize. Most categories are nonsense, although some may be useful. ‘Race’ is useless, pernicious nonsense.”

            The question of whether or not biological research into racial difference is useful still divides the scientific community. What seems to bother Reich above all is not that deeper racial differences may exist, but that biological research on these differences isn’t being done, at least not properly and not enough, so we just don’t know. Of course part of the reason for this is the longstanding scientific taboo against what might be considered race research, which has kept race off the table in mainstream biology since the end of World War II—although certainly not off the table in social science, which has built an enormous body of work on the topic. We have plenty of data on racial gaps in income, health, and schooling. The reason for this is that race has been accepted by academics as a social reality, not a biological one. Race affects how we live, but not who we are genetically.

            Reich, however, appears to find this unfair. “We’ve been silenced by the great anxiety that we feel talking about these things, and by the history of abuse of genetics by people seventy years ago or eighty years ago,” he says.

            He is probably not the only scientist who would like to be free of “the great anxiety” caused by eugenicists and scientific racists in the past. But that freedom would also have to come with responsibility. As the devastating mistakes of the nineteenth and early twentieth centuries proved, race research never goes well when society is racist. Although Reich insists that biological data as it stands makes racism impossible, I’m not so sure.

            Two days after I visit David Reich in his laboratory at Harvard, a party is held at the Cold Spring Harbor Laboratory, a world-class research institution on Long Island that was the site of the Eugenics Record Office until 1939. The celebration marks the ninetieth birthday of James Watson, one of the legends of twentieth-century genetics who, with Rosalind Franklin, Francis Crick, and Maurice Wilkins, helped discover the double-helix structure of DNA, for which Watson, Crick, and Wilkins won a Nobel Prize in 1962. Watson went on to become the laboratory’s director in 1968 and was crucial in helping to get it funding over the years and building its reputation. A Grammy Award–winning pianist is invited to give a performance at the party, with no fewer than eight Nobel laureates among the four hundred guests.

            Yet it has been known for years that Watson holds racist and sexist views. He was famously derogatory about his former colleague, Franklin, who did much of the experimental work that helped him make the discovery that led to his joint Nobel Prize. He also told the Sunday Times in 2007 that he was “inherently gloomy about the prospect of Africa,” because “all our social policies are based on the fact that their intelligence is the same as ours—whereas all the testing says not really.”

            In 2010 David Reich witnessed James Watson’s racism firsthand when they were both at the Cold Spring Harbor Laboratory for a workshop on genetics and human history. Watson sidled up to him and asked him something along the lines of, “When are you Jews going to figure out why are you guys are so smart?” Reich was appalled. Watson openly compared Jewish people to Brahmins, high-caste Indians who are known for being overrepresented in universities and high-status jobs. Traditionally they are India’s educated, priestly class. Watson suggested that racial purity combined with millennia of selecting for scholarliness was the key to both Jewish and Brahmin success. He went on to make other racial slurs about Indians being servile, a trait he believed suited British colonizers, and about the Chinese, who he thought had been made genetically conformist by their society.

            I wonder what Reich took away from this encounter. If, as Reich asserts, understanding the scientific facts makes it so impossibly difficult to be racist, how does James Watson manage it?

            Reich hesitates. “Well, Watson is, you know, is probably more sexist than he is racist,” he tells me awkwardly. “I don’t know. I don’t know. He’s like uncontrollable. It’s impossible to control Jim Watson. He purposely wants to create, to annoy people, to scandalize people, so I don’t know. You can’t control everybody. I do think that. So, yeah, I don’t know.”

            There is a long pause, an uncomfortable half shrug.

            “I just don’t know.”