More on biology and race

August 29, 2017 • 9:15 am

by Greg Mayer

Jerry posted yesterday on an article at Quillette by Bo Winegard, Ben Winegard and Brian Boutwell on biology and race, commending it for its sensibleness. I thought I’d chime in with my own thoughts. Jerry’s a population geneticist and I’m a herpetologist, but our views turn out to be quite similar.

So, here, in a nutshell, is what biology has to say about race. To begin with, race is not a technical term in biology—it is used loosely for any differentiated subdivision of a species. For example, there is a fruit fly in Wisconsin that feeds on hawthorn and apple, and the flies that feed on the different trees are somewhat different, and so people refer to the “hawthorn race” and the “apple race”. Often, as in fact is true in this case, the term “race” is used because people aren’t quite sure exactly how different the forms are from one another.

In zoology, the term “geographic race” does have a well-defined meaning. It means that if you look at an individual of a species, you can tell where it is from, or conversely, that if you tell me where the individual is from, I can tell you what it looks like. For example, there’s a species of lizard in Jamaica that if you brought one back and showed it to me, I could tell you whether it’s from the vicinity of Kingston, or Montego Bay, or Negril, etc. Lizards from these various places are members of the same species because they interbreed with one another where they are in geographic proximity; they are geographic races because I can tell where they are from by looking at them. Geographic races, if they are given taxonomic names, are called subspecies.

With regard to humans, most of the genetic variability is within populations, not between local populations or races. This was pointed out by Dick Lewontin in 1972 (Dick, of course, was Jerry’s dissertation adviser, and my de jure adviser). However, just because most of the variation is within populations doesn’t mean you can’t tell where someone is from by looking at him. The geneticist A.W.F. Tony Edwards later called the mistaken notion that a majority of variation being within populations precludes identification of population membership “Lewontin’s Fallacy”. [I’ve no idea where I got the idea he was called “Tony”. I’ve never met him, and people who do know him have assured me he’s called “Anthony”.]

As a former student of Lewontin’s, I’m not especially fond of Edwards’ choice of term, but nonetheless Edwards is entirely correct. It is of crucial importance to note that the scientific questions asked by Lewontin and Edwards were different. Lewontin asked “What proportion of genetic variation (in the analysis of variance sense) in humans is within and among populations?” The answer is that roughly 85% is within populations, the rest among local populations and races. That is the answer Lewontin gave in 1972, and it is entirely correct, confirmed by much more molecular data since that time. Edwards asked “Can individual humans be assigned to races from genetic data?”, or, alternatively, “Can human races be diagnosed (in the taxonomic sense of subspecies)?” The answer is yes, they can. Edwards shows that his answer to his question is entirely compatible with Lewontin’s answer to Lewontin’s question. A paper by Rosenberg et al. (2002) clearly illustrates for a large data set the truth of both Lewontin and Edwards’ answers to their respective questions. Lewontin goes on from his finding (with which Edwards entirely agrees), to argue further that this level of difference between races is not worthy of taxonomic recognition. Edwards doesn’t actually express an opinion about whether human races should be recognized taxonomically, but does show that the 85/15 division of within/among population variation is no bar to doing so.

One thing a bit off in the Quillette piece is their claim that Lewontin’s conclusion “was based on a peculiar way of measuring genetic variation.” It was not; it was based on a perfectly natural and obvious way of measuring genetic variation, and, indeed, Dick was right, as Edwards acknowledged. The distinction between single and multi-locus genotypes mentioned by Winegard et al. does not at all nullify Lewontin’s conclusion as to the apportionment of variation. What Edwards showed very clearly is that multi-locus genotypes allow individuals to be reliably assigned to populations, even when most of the variation is within populations. In understanding patterns of genetic variation in humans, it is very important to see that Lewontin and Edwards asked different questions, and that they are both right in their answers to their respective questions.

Lewontin and Edwards agree on the moral equality of human beings; Edwards just doesn’t want that moral equality to depend on any contingent facts of genetic similarity. Lewontin wouldn’t want it to, either, but sees the high genetic similarity among human races (genetic similarity is much lower among races in some other species) as empirical reinforcement for his moral conclusion. The problem with basing human moral and civil equality on empirical claims about human biological similarity is that such claims may prove to be mistaken. Because it does not depend on some empirical finding which new data may put into question, I think Edwards has the more robust basis for his moral conclusion.

As Edwards sums up:

“But it is a dangerous mistake to premise the moral equality of human beings on biological similarity because dissimilarity, once revealed, then becomes an argument for moral inequality.”

Edwards, A.W.F. 2003. Human genetic diversity: Lewontin’s fallacy. BioEssays 25:798–801. pdf

Lewontin, R.C. 1972. The apportionment of human diversity. Evolutionary Biology 6:381-398. pdf

Rosenberg, N.A., J.K. Pritchard, J.L. Weber, H.M. Cann, K.K. Kidd, L.A. Zhivotovsky, and M.W. Feldman. 2002. Genetic structure of human populations. Science 298:2381-2385. pdf

25 thoughts on “More on biology and race

  1. This is absolutely superb. I’m in my final semester of a 35 year career of teaching and research in genetics and evolution and am teaching both courses in it. I look forward to incorporating Greg’s synthesis into both.

  2. The biggest problem with race is a semantic one, but everyone must be so specific on language terminology, otherwise the differences are magnified into moral judgement. It then becomes as absurd as saying the Apple race is superior to the Hawthorne race.

    1. I might disagree with this. I agree with Edwards that morality has to be completely and utterly separated from biology. If not claims of superiority will inevitably and legitimately creep in.
      If there was general agreement in society that long-distance running ability was the most useful quality to have. If this could be backed up by showing that people with this ability had much richer lives. Then it would be hard to argue against the idea that East Africans were the superior race unless one a priori ruled out the idea of superiority on moral grounds.

  3. I was under the mistaken impression that Lewontin made a nucleotide by nucleotide comparison of individuals but used a consensus sequence comparison of self-described races.

    With hesitation I’d say my original claim (on this site) is still correct: that any apparent paradox between Lewontin’s and Edward’s results are resolved when one considers that the vast majority of variation between individuals isn’t doing anything, but within that are a small number of variants shared by ethnic groups that contribute to differences.

  4. Thanks for this post Greg, as well as for Jerry’s post yesterday directing to that article. The issue is a confusing one for lay people because nearly everyone now automatically insists that all research shows there are no races at all, on any level. This laid it out as clearly as possible–I’m probably as close to understanding it as I’m going to get.

  5. Thank you to Greg Mayer for a very clear and robust statement about the matter.
    I think some people without adequate background or patience will not take the time or energy to comprehend and I have found myself stuttering trying to put this kind of clear argument into a 30 sec.sound bite. The word race elicits pretty immediate knee jerks- even from folks,I feel, should know better.Treacherous waters.

  6. The last statement, ‘moral equality’ being linked to ‘biological similarity’ is not really that important. At least, I’ve not seen any direct examples of it.

    What I have seen is someone who is black telling me that I cannot understand the circumstances of their life because I am not black. Or a woman telling me I can never understand what it’s like to be a woman because I am not a woman.

    I would say ’empathy’ is linked to ‘biological similarity’ and it should not be. People do this a lot and I think it’s medieval and unproductive.

    I am a white heterosexual male and I claim anyone on the planet can know exactly what it is like to be me. If someone thinks that another person can not understand them, this is about as close to an insurmountable barrier to equality as any other.

  7. Looked at from another angle. Distinct human populations have been separated for (possibly) 50,000 years. These populations have survived in dramatically different environments. Why would the genes of these populations be frozen at the time of separation?

    1. have been separated for 50000 years? Not aware of any. In the deep past of our species there was long vicariance resulting in “racial” recognizable features, but the introgression has been happening for tens of thousands of years.

  8. One of my major pet peeves is that the general public, the media, and unfortunately a lot of academics (including biologists who should know better) keep making reference to the:

    HUMAN RACE instead of naming us what we are, a SPECIES.

    For a good history of geographically distinct “races” or subspecies and other population level recognition go to Ernst Mayr’s Animal Species and Evolution.

    But when and why did the public start calling all Homo sapiens members a SINGULAR RACE?

  9. So is this – race vs race definition – a [science] theory vs [common]
    theory thing, where science was first and the term was corrupted by common use?

    Lizards from these various places are members of the same species because they interbreed with one another where they are in geographic proximity; they are geographic races because I can tell where they are from by looking at them.

    I do not think that is exactly true for humans. We travel widely today, and I cannot tell where descendant individuals are born. Rather, I can tell what races (demes) are common in specific geographic locations for one reason or other.

    Jerry had an interesting analysis of whether or not Neanderthals are subspecies or not. If they (and Denisovans et cetera) are, it should be easy to push that into the above scheme.

  10. ” … he term “race” is used because people aren’t quite sure exactly how different the forms are from one another.”

    That’s an excellent way to put it…. or… interesting, at least…

    1. We could all start using the term alt-species or alt-specific instead of race. Subspecies should not be used because the first 3 letters could be construed as subservient.

      1. ,the question is says Alice whether you can make words mean what you want them to’ My words mean exactly what I want them to neither more nor less’ says Humpty Dumpty.
        Speaking again of race there is a nice passage at the beginning of ‘The Origin of Species’ about ‘land races’ of agricultural crops.

  11. “With regard to humans, most of the genetic variability is within populations, not between local populations or races. This was pointed out by Dick Lewontin in 1972…”
    Every time this point comes up, I am compelled to point out that this fact, by itself, does not imply anything at all about the reality of race or the amount of genetic differentiation between groups. When within-group diversity is high at the locus of interest, the additive between-group component of the diversity measures used by Lewontin, Lande and other older population geneticists is necessarily low. This would be true even if the groups belonged to different species and shared no alleles at all.

    I am not arguing that race is real, just that this part of the argument is dramatically wrong. See Jost, L. “Gst and its relatives do not measure differentiation”, Molecular Ecology 17: 4015-4026
    and many related articles of mine and others on the mathematics of diversity measures.

    1. “One thing a bit off in the Quillette piece is their claim that Lewontin’s conclusion “was based on a peculiar way of measuring genetic variation.” It was not; it was based on a perfectly natural and obvious way of measuring genetic variation”

      I think it is not the natural and obvious way of measuring genetic variation, at least if one hopes to use that quantity to infer the amount of genetic differentiation between the groups. It incorporates two mistakes when the diversity measure is heterozygosity, and one mistake if the diversity measure is entropy. The first mistake is to use a diversity measure that is not linear with respect to pooling of two equally large, equally diverse, completely distinct groups (no shared alleles). Both entropy and heterozygosity (the “genetic diversity” of old-school population geneticists)lack this property. The second mistake (which only applies to heterozygosity as a diversity measure, not to entropy) is the application of additive partitioning on a non-additive measure (heterozygosity).

      These errors can be corrected. Entropy and heterozygosity can be converted to effective number of alleles, which does have the properties of a true diversity measure, and these can be multiplicatively partitioned into independent within- and between-group components that really do tell us the amount of genetic differentiation between groups.

    2. By the way, you don’t need to read my papers to check this point. Just do the calculation yourself using entropy or heterozygosity as measures of diversity. Try calculating the ratio of within-group “variation” to total “variation” at a locus with 20 equally common alleles in one group, and 20 different equally-common alleles in the other (ie no shared alleles). This will be quite high even though the groups share no alleles and could be from different species or even different orders.

Leave a Reply