On Monday the NY Times ran an op-ed pice by Armand Marie Leroi, an evolutionary developmental biologist, on the concept of “race.” This paper reproduces an argument which has been gaining wider currency as a result of genetic studies: that, contrary to what anthropologists have to say on the subject, perhaps “race” isn’t a purely social construct, but does have some scientific validity after all.
After reading the article, it turns out that Leroi is playing word games.
The physical topography of our world cannot be accurately described in words. To navigate it, you need a map with elevations, contour lines and reference grids. But it is hard to talk in numbers, and so we give the world’s more prominent features – the mountain ranges and plateaus and plains – names. We do so despite the inherent ambiguity of words. The Pennines of northern England are about one-tenth as high and long as the Himalayas, yet both are intelligibly described as mountain ranges.
So, too, it is with the genetic topography of our species. The billion or so of the world’s people of largely European descent have a set of genetic variants in common that are collectively rare in everyone else; they are a race. At a smaller scale, three million Basques do as well; so they are a race as well. Race is merely a shorthand that enables us to speak sensibly, though with no great precision, about genetic rather than cultural or political differences.
Leroi is acting like Humpty Dumpty in Through the Looking Glass:
`When I use a word,’ Humpty Dumpty said, in rather a scornful tone, `it means just what I choose it to mean — neither more nor less.’
`The question is,’ said Alice, `whether you can make words mean so many different things.’
`The question is,’ said Humpty Dumpty, `which is to be master — that’s all.’
The sad fact is that race is not simply a shorthand for Leroi’s maps with elevations, contour lines, and reference grids, but refers to all kinds of cultural and political differences that have nothing to do with genetics. More importantly, these genetic difference map rather poorly on to our common sense notions about “race,” in ways that do nothing to help us understand the many important genetic issues that Leroi believes the term will help us face.
In order to make this point clearer than I ever could, I’ve invited my friend, population biologist Fredrick Gentz, a Ph.D. candidate at Temple University, to comment on the article.
Below are quotes from the article, followed by Fred’s commentary:
But this is not true when the features are taken together. Certain skin colors 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 from – and we usually get it right. To put it more abstractly, human physical variation is correlated; and correlations contain information.
Nothing new here. This is the anthropmetry of the early part of this century. It’s true that looking at a vast number of faces, body types, one can have a pretty good guess of continental origin. But what geneticists want to know is not “guess” estimates, but what is the error rate. Let me explain. Suppose I have a test for determining ‘race’ that is 75% accurate, and suppose I have another test that ascribes ‘disease type’ based on race that is 75% accurate. The chances of my picking the right race and picking the right disease for the race is (.75)(.75) = 0.563, or slightly better than flipping a coin.
Many European ‘racial’ diseases are quite restricted, but not entirely. Tay Sachs and other such afflictions are localized to various European groups, but also found elsewhere. If I was going to go by phenotype observations alone, I am quite sure most of my guesses of European ancestry would be quite erroneous (i.e. less than 75%). I would be better off asking each person where their parents and grand parents considered the ancestral home.
Indeed, a 2002 study by scientists at the University of Southern California and Stanford showed that if a sample of people from around the world are sorted by computer into five groups on the basis of genetic similarity, the groups that emerge are native to Europe, East Asia, Africa, America and Australasia – more or less the major races of traditional anthropology.
This is stuff done on Principle Components. The cluster analysis is rather interpretive, and alternative groupings can be generated. One must ask if the population origins were unknown would the same groupings be generated? Furthermore, if the study (I am not familiar with it) subdivides populations along continental lines, then it is a poor study as it obscures major regions of migration: like where are the Altaic genes among the Turks?, where is the region where the Europeans and Asians interact in Central Asia?; what about the slave trade from western Africa into southern Arabia and India? If all this study did was separate populations into five basic contiental masses, then it is useless as it obscured major events in human history.
Study enough genes in enough people and one could sort the world’s population into 10, 100, perhaps 1,000 groups, each located somewhere on the map.
Already we can theoretically distinguish one person from any other, alive or dead or unborn. Imagine 64 genes with 2 possible alleles each: then on the first gene you can separate the world into two populations, on the second an equal two (2×2 = 4), on the third gene, 2x2x2 = 8, and so on till 2^64, or 1.8×10^19 (more people then ever and will exist). So is everyone a unique ‘race’?
Soon it may be possible to identify your ancestors not merely as African or European, but Ibo or Yoruba, perhaps even Celt or Castilian, or all of the above.
‘Celt’ what is a Celt? The Celts were spread out across much of Europe, including Spain. Are the Spanish then Celts? If one says the Spanish derive a certain percentage of ancestry from the Celts, then are Latinos Celts?
The physical topography of our world cannot be accurately described in words. To navigate it, you need a map with elevations, contour lines and reference grids. But it is hard to talk in numbers, and so we give the world’s more prominent features – the mountain ranges and plateaus and plains – names. We do so despite the inherent ambiguity of words. The Pennines of northern England are about one-tenth as high and long as the Himalayas, yet both are intelligibly described as mountain ranges.
Names of topographical features are not ‘shorthands’ for geological inexpertise by the masses. The names are cultural products of an historical process by the people living in the regions. Too many people make the erroneous assumption that ‘race’ is a shorthand for scientific descriptions which are too complex for the majorities’ understanding. “Race’ is a cultural descriptor which serves multiple purposes. The above metaphor does not assist in the argument about ‘race’. Indeed, I could rewrite the above metaphor: there exist hidden strata which counfound the topological boundaries we commonly perceive on the surface. Likewise, there are hidden genetic ‘strata’ which confound our easy expectations of racial division we see on peoples faces.
One of the more painful spectacles of modern science is that of human geneticists piously disavowing the existence of races even as they investigate the genetic relationships between “ethnic groups.”
No geneticists are determining ‘genetic distances’ between populations. ‘Populations’ are abstract mathematical entities for which ethnic groups substitute. Identification of ethnic group is not made by the researcher, but by the group under study.
Such differences could be due to socioeconomic factors. Even so, geneticists have started searching for racial differences in the frequencies of genetic variants that cause diseases. They seem to be finding them.
This is important. By focusing research on racial differences (i.e. looking for genetic differences) social factors are likely to be overlooked or dismissed as irrelevant. There is only a limited amount of research money. Since the nineteenth century, the greatest advances have been made by relating health to living condition. Where genetics has played a significant role has been in programs to eradicate debilitaing genes from a population: e.g. Planned Parenthood.
That, it turns out, is much easier to do in people whose ancestors came from very different places. The technique is called admixture mapping. Developed to find the genes responsible for racial differences in inherited disease, it is only just moving from theory to application.
What researchers want is not ‘racial’ difference, but genetic distance. Quite different.
UPDATE: More from Alex Golub. Especially this article on “pharmacogenetics.”
UPDATE: More from Leroi here. With responses here. (via Gene Expression)
Golublog: An Anthropology Blog
Apr 03, 2005 @ 02:08:02
Since Kerim’s touched on the subject I’ll mention a few more things. First, Troy Duster (CV) has a nice, brief piece on pharmacogenetics that is worth checking out. Of course, those of you who are more old-school may prefer Buffon’s
Mar 23, 2005 @ 00:55:58
Suppose I have a test for determining ‘race’ that is 75% accurate, and suppose I have another test that ascribes ‘disease type’ based on race that is 75% accurate.
We now have tests that are close to 100% accurate, e.g. Am. J. Hum. Genet., 76:268-275, 2005: “Of 3,636 subjects of varying race/ethnicity, only 5 (0.14%) showed genetic cluster membership different from their self-identified race/ethnicity.”
The cluster analysis is rather interpretive, and alternative groupings can be generated. One must ask if the population origins were unknown would the same groupings be generated?
Yes, the results of Rosenberg et al. Science, Vol 298, Issue 5602, 2381-2385 did not use any information about the population affiliation of individuals. Individuals were stripped of all identifying information and were clustered based on allelic values alone. In the resulting clustering the five major continental groups emerged.
Mar 23, 2005 @ 14:29:37
1: All human categories are “cultural artifacts” in a sense – what is a “chair”? Where is the excact demarcation line between a chair and a recliner? What’s a “family”? Is a “family” a meaningless concept?
2: Thus, words aren’t about achieving some absolute precision – they are about usefulness in communications. “Race” is a way of communicating the fact that all people are not equally related. For many reasons – primarily cultural and geographical – people do not breed randomly – they breed with those who live nearby, and who are part of their cultural sphere.
3: Thus, genes won’t be spead out evenly over the whole of humanity – genetic “clusters” will tend to form according to geographical and / or cultural lines – creating “races”, or whatever one wants to call the “clusters” resulting from inbreeding.
4: As is often the case in science, using maths is better than words if you want to achieve much-desired precision in determing how inbred certain groups of people are (I.e, how much of a Race they are).
5: The math gets far too complex far too fast for being useful in everyday use, however. (Which goes for most areas) This is why by nature inprecise words can be useful even in describing such complex concepts as genetic relatedness. And, as study shows, self-identification into broad racial categories is often “good enough”.
6: If you want to debunk a study, actually reading it first is a plus.
7: Erm, so we should dismiss new fields of reseach a priori, because other factors have been more important during the last 150 years or so? As a philosophy of science, I don’t think that kind of approach is likely to be very fruitful…
8:” What researchers want is not ‘racial’ difference, but genetic distance. Quite different.”
Races are merely a way of organizing genetic distance in a fashion that is easier to grasp for us poor humans. Still, if you want to call different genetic clusters something else to wash out some of those goose-stepping connotations, fine by me. (Just remember to tell the rest of the world what term you decided on…)
Mar 24, 2005 @ 09:04:47
After reading the article, it turns out that Leroi is playing word games.
The participle “reading” isn’t attached to a subject. Better would be “After reading the article, you’ll see that…” or “When you read the article…”
Mar 24, 2005 @ 09:58:26
Pedant: I agree that it is an ugly construction. Thanks for pointing it out.
Mar 26, 2005 @ 00:26:42
The article says:
a…study … showed that if a sample of people from around the world are sorted by computer into five groups on the basis of genetic similarity, the groups that emerge are native to Europe, East Asia, Africa, America and Australasia…
Proving what? That people who live together breed together. But show average Denver residents a Palang hill tribe woman, and I doubt they’ve put her origins anywhere other than Africa. Genetically, maybe she would fit in more with other people from Burma or the Golden Triangle.
Mar 26, 2005 @ 13:15:49
Kerim,
‘Race’ is not just a matter of semantics. The usual interpretation of ‘race’ as selection on a population within a limited geographical region that confers fitness advantages. So northern populations among the Arctic have evolved larger nasal passages to accomodate them to survival in cold climates, is one example. Phenotypic difference alone is insufficient to clasify ‘racial’ differences. There has to be an associated fitness component.
Biological races have a number of characteristics, defined by Avise for subspecies: (1) geographically limitied region in which they live; (2) an unique history shared by members of the race; (3) phenotypic and behavioural differences from neighbouring members of their species; (4) an underlying genetic difference compared with members of their neigbouring species; and (5) a tendency towards endogamy. Depending on the focus one has, humans either fufill the above criteria or do not. However, one point needs to be made: reduced fecundity in matings between members of different races. One key means fo defineing biological race boundaries is hybrid zones. Such bybrids often are lower in fitness than either parent.
Now some agree with this basis for identifying biological races. Others, downplay notions of reduced hybrid fertility or geographical race fitness, opting only for genetic diversity between geographical populations as evidence of race. My own position is that genetic diversity between geographical populations is an insufficient basis for accounting for biological races. I would account for such ‘genetic distances’ based on models of ‘isolation by distance’ or other migratory barriers rather than race formation.
Above I noted that the concept of biological race is valuable for biologists. So here is one example of ‘race’ that I would accept as evidence of the model of increased fitness and reduced hybrid vigour: the hawthorn fly Rhagoletis represents a host-race, because some of the flies are attracetd to apples (not hawthorns) and mate predominantly with other flies attracted to the same food source. The reason of endogamy is the timing of fruiting of the respective host plants. Comparisons of chromosomes between the apple and hawthorn variety found differences between three chromosomes. Additionally, fly eggs from apple and hawthorn flies incubated in the lab had generation times seperated by 18 days, supporting the argument for a genetic basis. However, the flies are not completely separate species as apple and hawthorn flies mate with one another once the fruiting season is over. Yet, despite this, the two types of fly remain different from one another. There are other such examples with frogs and other species to make the concept of value. But in application to humans, the concept falls short.
One final note. While it is impossible to resolve at present, are archaic humans or even Neanderthal examples of bioligical races. In the transition period form erectus to sapliens, variant forms of Homo existed at the same time. These variant forms were regionally restricted, and their fossils allow for phenotypic differentiation (i.e. eye socket form, nasal passages etc.), and we may hypothesize they were endogamous. So based on these few characteristics, do the variant archaic humans that existed hundreds of thousands of years ago represent biological races? No one is sure, but there is a atronger argument here than with modern populations.
Missing Shades of Grue » Archive
Nov 27, 2005 @ 11:35:36
[...] The Nature Of Normal Human Variety Update to my past entry on the biology of race: Armand Leroi discusses the issue at edge.org (includes a video). He says: Of course, there will be people who object. There will be people who will say that this is a revival of racial science. Perhaps so. I would argue, however, that even if this is a revival of racial science, we should engage in it for it does not follow that it is a revival of racist science. Indeed, I would argue, that it is just the opposite. If you don’t think this has undesirable political ramifications, read here. Also look here for claims similar to Leroi’s. A fairer response to the NYT editorial can be found here, where you’ll be pointed to an interesting online quiz. There is also some critical commentary from Kerim Friedman and Alex Golub Edge: THE NATURE OF NORMAL HUMAN VARIETY A Talk with Armand Leroi [...]