Ó Indian Academy of Sciences

INVITED EDITORIAL

A family tree in every gene

Shortly after last year’s tsunami devastated the lands on because various American health agencies are making the Indian Ocean, The Times of India ran an article with race an important part of their policies to best protect the this headline: ‘Tsunami may have rendered threatened public – often over the protests of scientists. In the sup- tribes extinct’. The tribes in question were the Onge, plement, some two dozen geneticists offered their views. Jarawa, Great Andamanese and Sentinelese – all living Beneath the jargon, cautious phrases and academic cour- on the Andaman Islands and they numbered some 400 tesies, one thing was clear: the consensus about social con- people in all. The article, noting that several of the archi- structs was unraveling. Some even argued that, looked at pelago’s islands were low-lying, in the direct path of the the right way, genetic data show that races clearly do wave, and that casualties were expected to be high, said, exist. ‘Some beads may have just gone missing from the Emerald The notion that human races do not exist can be dated Necklace of India’. The metaphor is as colorful as it is well to 1972. This is when Richard Lewontin, a Harvard gene- intentioned. But what exactly does it mean? After all, in a ticist, wrote an influential review showing that most human catastrophe that cost more than 150,000 lives, why genetic variation can be found within any given ‘race’ should the survival of a few hundred tribal people have (Lewontin 1972). If one looked at genes rather than faces, any special claim on our attention? There are several pos- he claimed, the difference between an African and a Euro- sible answers to this question. The people of the Anda- pean would be scarcely greater than the difference bet- mans have a unique way of life. True, their material ween any two Europeans. A few years later he wrote that culture does not extend beyond a few simple tools, and the continued popularity of race as an idea was an ‘indica- their visual art is confined to a few geometrical motifs, tion of the power of socioeconomically based ideology over but they are hunter-gatherers and so a rarity in the mod- the supposed objectivity of knowledge’ (Lewontin 1974). ern world. Linguists, too, find them interesting since they Most scientists are thoughtful, liberal-minded and socially collectively speak three languages seemingly unrelated to aware people. It was just what they wanted to hear. any others. But The Times of India took a slightly differ- Three decades later, it seems that Dr Lewontin’s facts ent tack. These tribes are special, it said, because they are were correct, and have been abundantly confirmed by ever of ‘Negrito racial stocks’ that are ‘remnants of the oldest better techniques of detecting genetic variety (e.g. Barbujani human populations of Asia and Australia’. et al. 1997). His reasoning, however, was wrong. His error It’s an old-fashioned, even Victorian, sentiment. Who was an elementary one, but such was the appeal of his argu- speaks of ‘racial stocks’ anymore? After all, to do so would ment that it was only a couple of years ago that a Cambridge be to speak of something that many scientists and scholars University statistician, A. W. F. Edwards, put his finger on it say does not exist. If modern anthropologists mention the (Edwards 2003). concept of race, it is invariably only to warn against and The error is easily illustrated. If one were asked to dismiss it. Likewise many geneticists. ‘Race is a social con- judge the ancestry of 100 New Yorkers, one could look at cept, not a scientific one’, according to Dr Craig Venter – the colour of their skin. That would do much to single out and he should know, since he was first to sequence the the Europeans, but little to distinguish the Senegalese human genome. The idea that human races are only so- from the Solomon Islanders. The same is true for any cial constructs has been the consensus for at least 30 other feature of our bodies. The shapes of our eyes, noses years. and skulls; the colour of our eyes and our hair; the heavi- But now, perhaps, that is about to change. Last fall, the ness, height and hairiness of our bodies are all, individu- prestigious journal Nature Genetics devoted a large sup- ally, poor guides to ancestry. plement to the question of whether human races exist and, But this is not true when the features are taken to- if so, what they mean. The journal did this in part gether. Certain skin colours tend to go with certain kinds of eyes, noses, skulls and bodies. When we glance at a stranger’s face we use those associations to infer what

continent, or even what country, he or his ancestors came

Armand Marie Leroi, an evolutionary developmental biologist from – and we usually get it right. To put it more abstractly, at Imperial College in , is the author of “Mutants: On human physical variation is correlated; and correlations Genetic Variety and the Human Body”. contain information.

Journal of Genetics, Vol. 84, No. 1, April 2005 3

Genetic variants that aren’t written on our faces, but At a smaller scale, three million Basques do as well; so that can be detected only in the genome, show similar they are a race as well. Race is merely a shorthand that correlations. It is these correlations that Dr Lewontin seems enables us to speak sensibly, though with no great precision, to have ignored. In essence, he looked at one gene at a about genetic rather than cultural or political differences. time and failed to see races. But if many – a few hun- But it is a shorthand that seems to be needed. One of dred – variable genes are considered simultaneously, then the more painful spectacles of modern science is that of it is very easy to do so. Indeed, a recent study by scientists human geneticists piously disavowing the existence of showed that if a sample of people from around the world races even as they investigate the genetic relationships are sorted by computer into five groups on the basis of between ‘ethnic groups’. Given the problematic, even vici- genetic similarity, the groups that emerge are native to ous, history of the word ‘race’, the use of euphemisms is Europe, East Asia, Africa, America and Australasia – more understandable. But it hardly aids understanding, for the or less the major races of traditional anthropology (Rosen- term ‘ethnic group’ conflates all the possible ways in berg et al. 2002). which people differ from each other. One of the minor pleasures of this discovery is a new Indeed, the recognition that races are real should have kind of genealogy. You can find out where your ancestors several benefits. To begin with, it would remove the dis- came from – or even when they came, as with so many of junction in which the government and public alike defiantly us, from several different places (Parra et al. 1998). If embrace categories that many, perhaps most, scholars and you want to know what fraction of your genes are African, scientists say do not exist. European or East Asian, all it takes is a mouth swab, a Second, the recognition of race may improve medical postage stamp and $400 – though prices will certainly fall. care. Different races are prone to different diseases. The Yet there is nothing very fundamental about the con- risk that an African-American man will be afflicted with cept of the major continental races; they’re just the easiest hypertensive heart disease or prostate cancer is nearly way to divide things up. Study enough genes in enough three times greater than that for a European-American people and one could sort the world’s population into 10, man. On the other hand, the former’s risk of multiple 100, perhaps 1000 groups, each located somewhere on sclerosis is only half as great (Smith et al. 2004). Such the map. This has not yet been done with any precision, differences could be due to socioeconomic factors. Even but it will be. Soon it may be possible to identify your so, geneticists have started searching for racial differences ancestors not merely as African or European, but Ibo or in the frequencies of genetic variants that cause diseases. Yoruba, perhaps even Celt or Castilian, or all of the above. They seem to be finding them. The identification of racial origins is not a search for Race can also affect treatment. African-Americans res- purity. The human is irredeemably promiscuous. pond poorly to some of the main drugs used to treat heart We have always seduced or coerced our neighbors even conditions – notably beta blockers and angiotensin-con- when they have a foreign look about them and we don’t verting enzyme inhibitors. Pharmaceutical corporations understand a word. If Hispanics, for example, are com- are paying attention (Tate and Goldstein 2004). Many posed of a recent and evolving blend of European, new drugs now come labelled with warnings that they may American Indian and African genes, then the Uighurs of not work in some ethnic or racial groups. Here, as so often, Central Asia can be seen as a 3,000-year-old mix of West the mere prospect of litigation has concentrated minds. European and East Asian genes. Even homogenous groups Such differences are, of course, just differences in ave- like native Swedes bear the genetic imprint of successive rage. Everyone agrees that race is a crude way of predict- nameless migrations. ing who gets some disease or responds to some treatment. Some critics believe that these ambiguities render the Ideally, we would all have our genomes sequenced before very notion of race worthless. I disagree. The physical swallowing so much as an aspirin. Yet until that is tech- topography of our world cannot be accurately described nically feasible, we can expect racial classifications to in words. To navigate it, you need a map with elevations, play an increasing part in health care. contour lines and reference grids. But it is hard to talk in The argument for the importance of race, however, numbers, and so we give the world’s more prominent fea- does not rest purely on utilitarian grounds. There is also tures – the mountain ranges and plateaus and plains – names. an aesthetic factor. We are a physically variable species. We do so despite the inherent ambiguity of words. The Yet for all the triumphs of modern genetics, we know Pennines of northern England are about one-tenth as high next to nothing about what makes us so. We do not know and long as the Himalayas, yet both are intelligibly des- why some people have prominent rather than flat noses, cribed as mountain ranges. round rather than pointed skulls, wide rather than narrow So, too, it is with the genetic topography of our species. faces, straight rather than curly hair. We do not know The billion or so of the world’s people of largely Euro- what makes blue eyes blue. pean descent have a set of genetic variants in common One way to find out would be to study people of mixed that are collectively rare in everyone else; they are a race. race ancestry. In part, this is because racial differences in

4 Journal of Genetics, Vol. 84, No. 1, April 2005 Invited editorial looks are the most striking that we see. But there is also a human race will have gone extinct, and the human spe- more subtle technical reason. When geneticists map genes, cies will be the poorer for it. they rely on the fact that they can follow our ancestors’ chromosomes as they get passed from one generation to Postscript the next, dividing and mixing in unpredictable combina- tions. That, it turns out, is much easier to do in people This editorial first appeared on the Op-Ed pages of the New whose ancestors came from very different places (Parra York Times on March 16, 2005. It created a bit of ruckus. et al. 1998). Many members of the public responded to the NYT’s The technique is called admixture mapping. Developed Reader’s Forum, various “Blog” sites, or else wrote to me to find the genes responsible for racial differences in in- directly. I thought it might interest the readers of the Journal herited disease, it is only just moving from theory to appli- of Genetics to know what they said. cation (McKeigue et al. 2000; Smith et al. 2004; Patterson My respondents often began by identifying their politics et al. 2004). But through it, we may be able to write the (or else their politics were quite clear from their letter). genetic recipe for the fair hair of a Norwegian, the black- Those who did seemed to fall into roughly three groups: verging-on-purple skin of a Solomon Islander, the flat face (i) Liberals who have always believed that races are social of an Inuit, and the curved eyelid of a Han Chinese. We shall constructs, but who have never quite understood how this no longer gawp ignorantly at the gallery; we shall be able could be. They thanked me for clarifying the matter. (ii) to name the painters. Conservatives who have always believed that races are There is a final reason race matters. It gives us reason – real, but have never found a geneticist prepared to say so. if there were not reason enough already – to value and They thanked me for my courage and gloomily prophesy protect some of the world’s most obscure and marginalized a left-wing Fatwa. (iii) The Insane who believed that I am people. When the Times of India article referred to the racist. They condemned or praised me according to taste. Andaman Islanders as being of ancient Negrito racial Yet not all was reasonable praise, and unreasonable ac- stock, the terminology was correct. Negrito is the name cusation. There were some thoughtful complaints, of which given by anthropologists to a people who once lived three are worth addressing. throughout Southeast Asia. They are very small, very Some critics pointed out that I did not address scientific dark, and have peppercorn hair. They look like African racism. This is quite true, but I make no apology for it. pygmies who have wandered away from Congo’s jungles Over the past few decades, innumerable scholars have to take up life on a tropical isle. But they are not. shown that racist ideology has historically imbued the The latest genetic data suggest that the Negritos scientific study of human variation; indeed, the study of are descended from the first modern humans to have in- racist science is a sizeable scholarly industry (e.g. Barkan vaded Asia, some 100,000 years ago (Thangaraj et al. 1992; Graves 2001; Brace 2005). But I would deny that the 2003; Endicott et al. 2003). In time they were overrun or study of race – or to speak more technically, genetic struc- absorbed by waves of Neolithic agriculturalists, and later ture – is necessarily racist. And so, instead of a ritual mea nearly wiped out by British, Spanish and Indian colonialists. culpa on behalf of centuries worth of dead anthropologists Now they are confined to the Malay Peninsula, a few and geneticists, I thought it far more important to convey islands in the Philippines and the Andamans; everywhere how the scientific community’s view on the genetic struc- they are dying out (Weber 1997–2005). ture of human populations has recently changed – and why Happily, most of the Andamans’ Negritos seem to have it matters. survived December’s tsunami. The fate of one tribe, the Other critics acknowledged that while genetic structure Sentinelese, remains uncertain, but an Indian coast guard may exist, the word ‘race’ is irrevocably tainted and helicopter sent to check up on them came under bow and should not be used. This is a reasonable complaint. I merely arrow attack, which is heartening. Even so, Negrito popu- note that no other noun seems to do the job that ‘race’ lations, wherever they are, are so small, isolated and im- does, and that the way I use it is no different from the way poverished that it seems certain that they will eventually modern zoologists do when describing genetic structure in disappear. populations of Rift Lake cichlids, ladybirds or chimpanzees Yet even after they have gone, the genetic variants that (but see Jobling et al. 2004, p. 273 for another view). defined the Negritos will remain, albeit scattered, in the Finally, some critics argue that while my argument is people who inhabit the littoral of the Bay of Bengal and not racist, it aids racists for they will appropriate the au- the South China Sea. They will remain visible in the un- thority of my name, title, and the pages of the New York usually dark skin of some Indonesians, the unusually curly Times, to further their own agendas. Regrettably, this is hair of some Sri Lankans, the unusually slight frames of so. As such, I find myself in the company of those evolu- some Filipinos. But the unique combination of genes that tionary biologists who, critiquing some aspect of standard makes the Negritos so distinctive, and that took tens of Neo-Darwinian theory, find themselves cited with approval thousands of years to evolve, will have disappeared. A by creationists. Yet political ends – even fear of evil ones –

Journal of Genetics, Vol. 84, No. 1, April 2005 5 Armand Marie Leroi cannot dictate our understanding of the natural world. Lewontin R. C. 1974. The genetic basis of evolutionary change. Injustice can sometimes be the consequence of new know- Columbia University Press, NY. Smith M. W., Patterson N., Lautenberger J. A., Truelove A. L., ledge, but more often – far more often – it slips through the McDonald G. J., Waliszewska A., Kessing B. D., Malasky cracks of our ignorance. M. J., Scafe C., Le E., De Jager P. L., Mignault A. A., Yi Z., The volume of responses to my article showed that De The G., Essex M., Sankale J. L., Moore J. H., Poku K., race remains a topic of absorbing interest to the public. It Phair J. P., Goedert J. J., Vlahov D., Williams S. M., Tish- also suggests that the public have found the time-worn koff S. A., Winkler C. A., De La Vega F. M., Woodage T., Sninsky J. J., Hafler D. A., Altshuler D., Gilbert D. A., formulas offered by the scientific community unsatisfying; O’Brien S. J. and Reich D. 2004. A high-density admixture but then, I think, so have many individual geneticists and map for disease gene discovery in African Americans. Am. J. anthropologists. It is my hope that my article, sketchy Hum. Genet. (74), 1001–1013. though it was, contributes to public discussion about the Parra E. J., Marcini A., Akey J., Martinson J., Batzer M. A., nature of human variety. There is much at stake. Cooper R., Forrester T., Allison D. B., Deka R., Ferrell R. E. and Shriver M. D. 1998. Estimating African American ad- mixture proportions by use of population-specific alleles. Am. J. Hum. Genet. (63), 1839–1851. References Patterson N., Hattangadi N., Lane B., Lohmueller K. E., Hafler D. A., Oksenberg J. R., Hauser S. L., Smith M. W., O’Brien Barbujani G., Magagni A., Minch E. and Cavalli-Sforza L. L. 1997. S. J., Altshuler D., Daly M. J. and Reich D. 2004. Methods An apportionment of human DNA diversity. Proc. Natl. for high-density admixture mapping of disease genes. Am. J. Acad. Sci. USA. (94), 4516–4519. Hum. Genet. (74), 979–1000. Barkan E. 1992. The retreat of scientific racism: changing con- McKeigue P. M., Carpenter J. R., Parra E. J. and Shriver M. D. cepts of race in Britain and the United States between the 2000. Estimation of admixture and detection of linkage in wars. Cambridge University Press, Cambridge, UK. admixed populations by a Bayesian approach: application to Brace C. L. 2005. “Race” is a four-letter word: the genesis of a African-American populations. Ann. Hum. Genet. (64), 171– concept. Oxford University Press, Oxford and New York. 186. Edwards A. W. 2003. Human genetic diversity: Lewontin’s Rosenberg N. A., Pritchard J. K., Weber J. L., Cann H. M., fallacy. Bioessays. (25), 798–801. Kidd K. K., Zhivotovsky L. A. and Feldman M. W. 2002. Endicott P., Gilbert M. T., Stringer C., Lalueza-Fox C., Willerslev Genetic structure of human populations. Science. (298), E., Hansen A. J. and Cooper A. 2003. The genetic origins of 2381–2385. the Andaman Islanders. Am. J. Hum. Genet. (72), 178–184. Thangaraj K., Singh L., Reddy A. G., Rao V. R., Sehgal S. C., Graves J. L. 2001. The emperor’s new clothes: biological theories Underhill P. A., Pierson M., Frame I. G. and Hagelberg E. of race at the millenium. Rutgers University Press, New 2003. Genetic affinities of the Andaman Islanders, a vanishing Brunswick. human population. Curr. Biol. 2003. (13), 86–93. Jobling M. A., Hurles M. E. and Tyler-Smith C. 2004. Human Weber G. 1997–2005. The lonely islands: the Andamanese. evolutionary genetics: origins, peoples and diseases. Garland www.andaman.org. Science. Tate S. K. and Goldstein D. B. 2004. Will tomorrow’s medicines Lewontin R. C. 1972. The apportionment of human diversity. work for everyone? Nat. Genet. (36), S34–S42. In: Dobzhansky T., Hecht M. K. and Steere W. C. editors. (6), 381–398. Appleton-Century-Crofts, New York. ARMAND MARIE LEROI

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