Genetics, race and the methodology of differentiation

Whilst twenty-first century research into molecular genetics seemed to promise an end to outmoded racial stereotypes and typologies, it actually managed to revive discussions about biological differences among a number of geneticists. On the DNA of these debates and their implications for the future.

During the past century, geneticists have had a problematic relationship with the question of human ‘races’. While the notion of races stretches back much further in history, twentieth-century genetics often fuelled political ideologies and movements based on the idea that human beings can be divided into different biological groups. The most obvious example of this, of course, is the interplay between racial biology, eugenics and fascism that culminated in the Holocaust and the mass murder of Jews, Roma and other ‘inferior races’.

But even after the crimes of Nazism were exposed, eugenics was discredited and the UN in the early 1950s published its statement on the fundamental unity of humankind, many geneticists continued to assert that humans could be categorized into biological races.1

Rather than being erased from post-war scientific discourse, the concept of race was, as sociologist Troy Duster puts it, ‘buried alive’.2 Just five years after the evacuation of Auschwitz, immunologist William Boyd published Genetics and the Races of Man, in which he – opposing those who had ‘misused’ the term race – advocated a ‘scientific division of mankind into races’.3

Boyd’s book sparked a number of post-war scientific works presenting typologies of the human races. Its representatives were not only to be found in notorious academic journals like Mankind Quarterly, but also in high-profile academic departments of population genetics and biological anthropology.4 Even in cases where the word ‘race’ was replaced by more technical terms such as ‘population’ or ‘genetic cluster’, the idea that human beings belong to separate groups by virtue of their genetic structure persisted.

DNA left handed double helix

Z-DNA: left-handed double helix. Image by mcmurryjulie on Pixabay.

The molecularization of race

During a short period around the turn of the millennium, however, the new field of molecular genetics – the exploration of the human genome at the DNA level – seemed to be putting an end to the old racial-typological project. When researchers in the Human Genome Project (HGP) presented their map of the human genome in the summer of 2000, a finding which indicated that all human DNA is 99.9% identical, hopes were expressed that the concept of race would finally lose its scientific legitimacy.

‘The most important fact of life on this earth’, American President Bill Clinton stated at the HGP press conference, ‘is our common humanity’. One of the project’s initiators, geneticist Craig Venter, asserted that the word race ‘has no genetic or scientific basis’.5 Clinton and Venter hoped that similarity – the fact that the genetic difference between people was negligible – would erode outdated ideas about biological race.

This article was originally published in the Swedish philosophy journal ‘Fronesis’. Issue 66-67 deals with genetics and race.

Instead, the opposite seemed to happen. Rather than putting an end to geneticists’ preoccupation with race, the presentation of the human genome effectively revived the discussion about biological differences. In the 2000 article ‘Unequal by Nature,’ geneticist James Crow wrote: ‘Most of the [genetic] differences that we notice are caused by a very tiny fraction of our DNA. Given six billion base pairs [DNA] per cell, a tiny fraction – 1/1000 of six billion base-pairs – is still six million different base pairs per cell. So there is plenty of room for genetic differences among us.’6 Crow thus rejected the idea that the one-hundredth of a percent of genetic difference was insignificant. The actual differences between White, Asian and African individuals, he argued, justified a continued use of the word race.

During the following years, a number of geneticists would follow suit. In a high-profile 2000 study in Science, the Human Genome Diversity Project geneticist Marc Feldman argued that humans could be divided into six genetic clusters corresponding to geographic regions such as Europe, East Asia and Africa.7

In the same year, medical researchers Esteban Burchard and Elad Ziv asserted that ‘[t]he past two decades of research in population genetics has shown that the greatest genetic differentiation […] occurs between continentally separated groups’ and that ‘[i]gnoring racial and ethnic differences […] will not make them disappear.’8

In 2005, a team of researchers took DNA samples from a number of White, African-American, East Asian and Hispanic individuals in the United States and concluded that the four ‘genetic clusters’ that emerged in their analysis were ‘highly correlated’ with the study participants’ self-identified ethnicities.9 A year later, American Senator Barack Obama suggested that the US government should finance research on ‘race, genomics and health’ in order to investigate how ‘molecular genetic screening, diagnostics and treatments may be used to improve the health and health care of racial and ethnic minority populations.’10

Rather than shattering biological ideas about racial differences, the new field of molecular genetics thus ended up reinforcing them. The emphasis on similarity gave way to an ever-increasing focus on difference. The notion of race as a social construct rather than a material reality, as biologist Armand Marie Leroi wrote in early 2005, was unravelling.11

The concept of race was becoming ‘molecularized’: if genetics had traditionally assumed that race could be distinguished through phenotypic attributes (such as blood type or cranium dimensions), it was now assumed to be expressed through genotypic variations in human DNA.

Such assumptions effectively opened up for a new kind of molecularized scientific racism. In a 2005 article, psychologist David Rowe wondered whether the new DNA technologies would be able to prove intelligence differences between Black and White individuals. ‘[I]n the next few decades’, Rowe argued, ‘many genetic racial differences are likely to be discovered.’12 Over the next few years, a number of scientists speculated on the links between DNA, race or nationality and phenomena such as criminality, impulsivity and intelligence.

Molecularized scientific racism culminated in 2014, when science journalist Nicholas Wade published his book A Troublesome Inheritance: Genes, Race and Human History. Echoing eighteenth-century racial typology, Wade claimed that molecular genetics had proved the existence of ‘three major races’: Africans, Caucasians and East Asians. By studying so-called ancestry-informative markers in the genome, Wade argued, geneticists could effectively identify the races of different individuals.

Wade went on to argue that the respective characteristics of Africans, Caucasians and East Asians were ultimately caused by natural selection: the genetic mutations that were most appropriate for survival in a particular historical context had created certain dominant behaviours. Jewish intelligence, European entrepreneurship and Asian collectivism could be understood as the result of a genetic-historical process which had successively laid the foundation for entire societies. As Wade put it:

[The differences between human societies] stem from the quite minor variations in human social behavior […] that have evolved within each race during its geographical and historical experience. These variations have set the framework for social institutions of significantly different character. It is because of their institutions – which are largely cultural edifices resting on a base of genetically shaped social behaviors – that the societies of the West and of East Asia are so different, that tribal societies are so unlike modern states, and that rich countries are rich and poor countries deprived.13

The fact that human behaviour is genetically coded, Wade claimed, was proven by science; those who disputed this were either Marxists or academics deceived by multicultural dogma. Despite the references to contemporary molecular genetics, however, A Troublesome Inheritance faced harsh criticism from the scientific community. Shortly after the book was published, over a hundred scientists wrote a letter where they distanced themselves from Wade, making clear that his theories had ‘no support from the field of population genetics.’14

One of those who signed the letter was population geneticist David Reich, who remarked that ‘our findings do not even provide a hint of support in favour of Wade’s guesswork.’15 Despite his criticism of Wade, Reich would soon publish a book in which he came to surprisingly similar conclusions himself.

David Reich’s Who We Are and How We Got Here

As the Principal Investigator at Harvard University’s David Reich Lab – one of the world’s leading laboratories for the analysis of prehistoric genomes – David Reich is a key figure in archaeogenetic research. In his 2018 study Who We Are and How We Got Here, he describes what he calls ‘the ancient DNA revolution’ and its advances over the last decade.

The DNA revolution, Reich claims, isn’t only ‘disrupting our assumptions about the past’, but also resolving longstanding controversies in archaeology, history and anthropology.16

At first glance, Reich’s book can be described as a summary of what is currently known as archaeogenetics. But Who We Are is also a powerful – and rather contradictory – contribution to the twenty-first-century debate on genetics and race. In the opening of the book, Reich joins the ranks of those who hold that molecular genetics has shattered the idea of discrete biological races. He writes:

[T]his long-held view about ‘race’ has just in the last few years been proven wrong. […] A great surprise that emerges from the genome revolution is that in the relatively recent past, human populations were just as different from each other as they are today, but that the fault lines across populations were almost unrecognizably different from today. […] Present-day populations are blends of past populations, which were blends themselves. The African American and Latino populations of the Americas are only the latest in a long line of major population mixtures (xxiv).

Archaeogenetics has, in other words, revealed that present-day populations don’t represent any homogeneous genetic entities that can be traced back thousands of years, but are the result of constant mixtures between different groups. As a consequence of this finding, political movements that project racist hierarchies backwards into the past will be undermined by scientific facts.

‘[I]deologies that seek a return to a mythical purity’, Reich writes, ‘are flying in the face of hard science.’ The ancient DNA revolution, he continues, will ‘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’ (273). As archaeogenetics exposes world history as a process of incessant mixing, racist notions of purity, origin and continuity will be discarded.

While Reich criticises notions of purity and racial categorizations, however, he nevertheless bases his own analysis on a systematic division of people into genetic groups. This isn’t merely the case regarding his seemingly unproblematic use of terms such as ‘Europeans’, ‘East Asians’ and ‘West Africans’ as genetic entities, but also his recurring claim that there actually exist – and have existed – ‘unmixed’ populations.

‘[T]he people of India today,’ Reich writes at one point, ‘are the outcome of mixtures between two highly differentiated populations […] who before their mixture were as different from each other as Europeans and East Asians are today.’ Before these population groups mixed, he continues, ‘there were unmixed populations’ (259). Later in the book, he similarly asserts that world’s populations of today are ‘mixtures of highly divergent populations that no longer exist in unmixed form’ (259).

Reich’s arguments are thus based on an unmistakable ambivalence: while archaeogenetics has shown that all human beings are mixed, there also exist ‘unmixed’ or ‘highly divergent’ populations. On the one hand, races don’t exist; on the other, ‘Europeans’ and ‘East Asians’ are portrayed as genetically distinct groups. This ambiguity comes to a head in a passage in which Reich seems to revive an old tradition of racial typology:

The physical similarity of West Eurasian populations was recognized in the eighteenth century by scholars who classified the people of West Eurasia as ‘Caucasoids’ to differentiate them from East Asian ‘Mongoloids’, sub-Saharan African ‘Negroids’, and ‘Australoids’ of Australia and New Guinea. In the 2000s, whole-genome data emerged as a more powerful way to cluster present-day human populations than physical features (93).

It’s difficult to read this quotation as anything other than Reich reviving traditional scientific racism, albeit with new molecular genetic tools. The gradual turn of Who We Are from a critique of the concept of race to jargon echoing old-time scientific racism is accentuated in the book’s final section, where Reich attacks the ‘orthodoxy’ – primarily represented by the left-wing geneticist Richard Lewontin – that there are no substantial biological differences between human groups.

In terms reminiscent of Wade’s A Troublesome Inheritance, Reich argues that this alleged orthodoxy won’t be able to ‘survive the onslaught of science’ (254) and that the DNA revolution is ‘revealing hard evidence’ that such differences in fact exist (251). Reich writes:

We cannot deny the existence of substantial average genetic differences across populations, not just in traits such as skin color, 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.

And continues: ‘These differences are just the beginning’ (255).’ He goes on to give examples of studies in molecular genetics which claim to have demonstrated links between peoples’ DNA and their education level and intelligence. Such studies, Reich claims, reveal what is ‘likely to be only the tip of an iceberg of behavioral traits affected by genetics’ (257). One must consider the ‘genetically predicted performance’ that individuals from different populations possess (266).

With these points, Reich reaches the conclusion of his discussion on genetics and race. If scientists don’t dare to broach the subject of genetic differences between populations, he writes, the stage will be set for pseudo-scientific speculations à la Nicholas Wade:

[W]e 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. The approach of staying mum, of implying to the public and to colleagues that substantial differences in traits across populations are unlikely to exist, is a strategy that we scientists can no longer afford, and that in fact is positively harmful (258).

With these words, Reich has come full circle. Having opened his book with a critique of the concept of race, he concludes it with a call for a scientific approach to the biological differences that have traditionally gone by the name of race. For Reich, the fundamental problem isn’t that geneticists reinforce and naturalize notions of race, but that they give too little attention to the biological differences between people. Despite the rhetoric of mixing, it’s the differences that matter in the end.

Genetics, mixing and differentiation

How should we understand the paradoxes of Who We Are? Why does David Reich’s critique of racism and sweeping racial categorizations turn into genetic essentialism and biologically deterministic ideas that individuals’ behaviours are based on their affiliation to a genetic group?

The key to understanding this paradox lies in the concept of mixing, which, despite being presented as the antithesis to the idea of distinct biological races, actually incites notions of purity and origin. The basic problem is that mixing, as pointed out by anthropologist Kimberly TallBear, is ‘predicated on the notion of purity.’17.

The genetic concept of mixing, anthropologists Nicholas Passalacqua and Marin Pilloud note in a similar vein, ‘imply that there are groups that are not admixed, or rather, that there are source populations which are solely of a certain ancestry.’18 The point is simple: nothing can be mixed that wasn’t first unmixed, otherwise the concept of mixing wouldn’t have any meaning.

Population geneticists’ claim that contemporary human beings are ‘mixtures’ of older groups implicitly asserts that these older groups were at some point unmixed, which, in turn, means that today’s populations could – at least in theory – also be unmixed.

Rather than undermining essentialist ideas about ‘pure races’ or ‘unmixed populations’, the rhetoric of mixture reproduces them. The seemingly anti-racist talk about mixing is based on the tacit assumption that there are, or have been, genetically pure groups.

As noted above, Who We Are is composed of seemingly paradoxical claims: all populations are mixed, but ‘unmixed populations’ also exist. On closer inspection, however, these claims are not actually contradictory, but the logical conclusion of the mixing rhetoric employed by contemporary population geneticists.

Against this backdrop, it’s also possible to understand why Reich, despite purporting to debunk racist ideas about fundamental differences between people, ends up in a position where he highlights the significance of these differences. Like all branches of genetics, archaeogenetics is based on what could be called the methodology of differentiation: for DNA sequences to have any meaning, they must be compared with – and differentiated from – other sequences from other individuals.

In archaeogenetic contexts, this mainly amounts to separating and giving labels to the genetic clusters that appear when scientists compare the DNA of prehistoric individuals. Regardless of whether this naming is done on geographic, temporal or archaeological-cultural grounds, it establishes a kind of absolute difference in which different clusters are constructed as essentially different genetic groups.

As archaeologist Susanne Hakenbeck has pointed out, the archaeogenetic method is based on letting DNA samples from prehistoric individuals ‘stand in for entire archaeological cultures which, in turn, represent ethnic groups.’19

This applies to David Reich’s work, where a relatively limited numbers of prehistoric DNA samples lay the basis for statements about ‘the Northern European population’, the ‘Eastern European hunter-gather population’ or ‘the Finnish population’ – geographically or ethnically defined collectives whose very meaning are based on the assumption that their members share a genetic structure that is qualitatively different from other groups.

If prehistoric individuals can be divided into genetically separate groups in this way, the same must apply to modern humans. When Reich concludes his book by emphasizing ‘the substantial differences across populations’, it’s a conclusion that doesn’t contradict, but completely dovetails with the genetic essentialism that informs his analysis of human history.20

Rather than disrupting biological notions about race, Who We Are is ultimately a book that seeks to prove the existence and significance of race in the past as well as in our own times.


Shortly after the release of Who We Are, David Reich published an essay in The New York Times in which he summarised his position on genetics and race. While Reich admitted that genetics could be misused for racist purposes, he also claimed that it was no longer possible to turn a blind eye to the ‘substantial average genetic differences across populations’ and that ancient DNA proved that ‘many of today’s racial constructs are real.’

After yet again referring to studies which had allegedly demonstrated the link between genes, intelligence and educational attainment, Reich stressed that individuals from different populations had different genetic preconditions for cognition and behaviour. It would, he wrote, be ‘impossible – indeed, anti-scientific, foolish and absurd – to deny those differences.’

He concluded this appeal for a new concept of race with a reference to his anti-racist convictions. ‘Arguing that no substantial differences among human populations are possible’, he wrote, ‘will only invite the racist misuse of genetics that we wish to avoid.’21

A week later, 67 scientists and researchers in the natural and social sciences, humanities and law published an open letter on Buzzfeed criticizing Reich’s ideas. If race is simply used as a term for a group of individuals who share a genetic variation, they argued, it would be possible to find races everywhere. Given that the genetic difference between individuals amounts to 15 million base pairs of DNA (of three billion base pairs per individual), statistically relevant patterns could be found wherever one wanted to look, they argue.

Given random variation, you could genotype all Red Sox fans and all Yankees fans and find that one group has a statistically significant higher frequency of a number of particular genetic variants than the other group,’ the authors noted. ‘This does not mean that Red Sox fans and Yankees fans are genetically distinct races.’22

The central problem with Reich’s arguments was that he equated genetic difference and race. The fact that biological differences exist doesn’t necessarily mean that races exist. To achieve a better understanding of the historical and political problems associated with the concept of race, geneticists should collaborate with their colleagues in the social sciences, humanities and public health.

The controversy surrounding Who We Are shows that the debate on genetics and race is far from over. The twenty-first century mapping of the human genome and the subsequent realization that all humans are genetically very similar seem, paradoxically, to have bolstered the notion of genetically distinct races.

If xenophobic and chauvinist movements continue to gain ground, it’s likely that there will be more incentives for genetic research focused on the material reality of race. Yet the question of whether tomorrow’s genetics will open a ‘backdoor to eugenics’, as Troy Duster puts it, will ultimately be settled by the researchers themselves.23

Only they can decide if they want to keep racializing the 0.01% that differentiates one human from another, and thereby provide continued legitimacy to ideas about biologically discrete races. That is, in the end, an ethical and political issue.

UNESCO, “Statement on Race” (1950), in Four Statements on the Race Question (Paris: UNESCO, 1969).

Troy Duster, ‘Buried Alive: The Concept of Race in Science’. In Genetic Nature/Culture: Anthropology and Science Beyond the Two-Culture Divide, edited by Alan H. Goodman, Deborah Heath and M. Susan Lindee (Berkeley: University of California Press, 2003).

William C. Boyd, Genetics and the Races of Man: An Introduction to Modern Physical Anthropology (Boston, Little Brown, 1950), p. 198.

See Gavin Schaffer, ‘“Scientific Racism Again?”: Reginald Gates, the Mankind Quarterly and the Question of “Race” in Science after the Second World War’, Journal of American Studies 41, no. 2 (2007): pp. 253-278.

As quoted in ‘Reading the Book of Life: White House Remarks on Decoding of Genome’, The New York Times, 27 June 2000.

James F. Crow, ‘Unequal by Nature: A Geneticist’s Perspective on Human Differences’, Daedalus 131, no. 1 (2002): p. 83.

Noah A. Rosenberg et al., ‘Genetic Structure of Human Populations’, Science 298, no. 5602 (2002): pp. 2381-2385.

Esteban Burchard et al., ‘The Importance of Race and Ethnic Background in Biomedical Research and Clinical Practice’, New England Journal of Medicine 348, no. 12 (2003): pp. 1171,1174.

Hua Tang et al., ‘Genetic Structure, Self-Identified Race/Ethnicity, and Confounding in Case-Control Association Studies’, American Journal of Human Genetics 76, no. 2 (2005): pp. 268-275.

As quoted in Duana Fullwiley, ‘The Molecularization of Race: Institutionalizing Human Difference in Pharmacogenetics Practice’, Science as Culture 16, no. 1 (2007): pp. 24, 25.

Armand Marie Leroi, ‘A Family Tree in Every Gene’, The New York Times, 14 March 2005.

David C. Rowe, ‘Under the Skin: On the Impartial Treatment of Genetic and Environmental Hypotheses of Racial Differences’, American Psychologist 60, no. 1 (2005): p. 69.

Nicholas Wade, A Troublesome Inheritance: Genes, Race and Human History (New York: Penguin, 2014), p. 241. (Emphasis added.)

Graham Coop and Michael B. Eisen, ‘Letters: “A Troublesome Inheritance”, The New York Times Book Review, 8 August 2014.

As quoted in Michael Balter, ‘Geneticists Decry Book on Race and Evolution’, Sciencemag.com, 8 August 2014.

David Reich, Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past (Oxford: Oxford University Press, 2018), p. xxiii.

Kimberly TallBear, Native American DNA: Tribal Belonging and the False Promise of Genetic Science (Minneapolis, MN: University of Minnesota Press, 2013), p. 5

Nicholas V. Passalacqua and Marin A. Pilloud, Ethics and Professionalism in Forensic Anthropology (Place: Academic Press, 2018), p. 92.

Susanne E. Hakenbeck, ‘Genetics, Archaeology and the Far Right: An Unholy Trinity’, World Archaeology 51, no. 4 (2019): p. 3.

Reich, p. 251.

David Reich, ‘How Genetics Is Changing Our Understanding of “Race”’, The New York Times, 23 March 2018.

Jonathan Kahn et al., “How Not to Talk About Race and Genetics,” in Buzzfeed News, 30 March 2018. See https://www.buzzfeednews.com/article/bfopinion/race-genetics-david-reich.

Troy Duster, Backdoor to Eugenics (New York: Routledge, 1990).

Published 4 January 2021
Original in Swedish
First published by Fronesis 66–67/2020

Contributed by Fronesis © Daniel Strand / Fronesis / Eurozine



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