One scientific topic that I have previously discussed is the biological validity of the race concept. This, unfortunately, has become necessary, because some people, perhaps with political motivations, assert, contrary to the evidence, that “race does not exist” and that race is a “social construct” with “no biological foundation.” These views have been effectively refuted in various forums, and more objective researchers support the race concept as well, if for no other reason the important medical implications of racial differences.

One popular and misinterpreted finding that has been eagerly grasped at by those who preach that “race is not real” is derived from the work of Richard Lewontin, which demonstrated that more genetic variation exits within rather than between groups. I have previously explained how Lewontin’s finding in no way discredits the race concept. However, there are “anti-racist” activists who still claim, based on their misinterpretations of population genetics, that individual Europeans (“whites”) can be more genetically similar to sub-Saharan Africans (“blacks”) than to other Europeans. Until now, there has been no formal proof that this assertion is incorrect. I am now pleased to say that a recent scientific paper has delved into this very topic and that the findings of this paper clearly demonstrate that the race deniers are wrong. First, let me give a brief introduction for the sake of clarity.

A number of scientific studies have shown that it is possible to genetically cluster individuals to their self-identified race with near 100% accuracy. Further, racial categories can be determined by the genetic data even without any a priori information about the groups involved. In other words, racial groups can be empirically observed through genetic analysis without any prior assumptions about these groups by the researchers.

However, does that imply that individual members of these races will always be more genetically similar to members of their own racial group compared to members of other groups? Or, are genetic clustering and individual genetic similarity so different that this may not be always so? Can individuals share more genetic similarity to members of other groups rather than to members of their own group, even if everyone is properly clustered with their self-identified race? In other words, can there be significant genetic overlap between individuals on the fringes of, say, the European and African clusters?

These are the questions asked, and answered, in the paper Genetic Similarities Within and Between Human Populations by Witherspoon et al., Genetics 176, pgs. 351-359, 2007. I will simplify the authors’ statements and analogies so as to make the work more understandable to the broad readership; although this may mean that certain detailed specifics are glossed over, the main “take home” points and essential interpretations remain intact. And, since the paper is available online at no cost, any reader interested in delving into the scientific details can do so at their leisure.

The authors introduced the metric “w”, which they defined as:

… the frequency with which a pair of individuals from different populations is genetically more similar than a pair from the same population.

In other words, what is being determined with “w” is the frequency with which, for example, individual whites and individual blacks may be more similar to each other than to members of their own race. This measurement, which is based upon gene by gene comparisons between individuals, is different from the two clustering measurements that the authors compare to “w.” Unlike “w”, the clustering measurements incorporate population-level genetic information, and thus consider the “aggregate” qualities of the population’s genetic information. To put it simply, and bypassing many details, “w” compares individuals to each other, while clustering is, essentially, comparisons of individuals to the “genetic average” (or “centroid”) of different populations. By crude analogy, we can consider physical traits. “W” would be analogous to how similar two individuals are to each other in height, weight, eye color, skin color, hair color, facial features, etc. Clustering, in contrast, is more analogous to how similar each individual is to the average measurements of height, weight, eye color, etc. for any group. Thus “w” can tell us how similar individuals are to each other, while clustering tells us whether an individual is more similar to one group or another. Clustering allows us to “bin” (or “cluster”) individuals as belonging to one group or another.

combinations of colors for specific marbles. For example, person A may have red marbles for #1, 6, and 15; blue marbles for # 3, 10, 33, and 95; green marbles for # 7, 8, 22, and 84, and a yellow marble for # 38. If this particular, specific combination of colored marbles is of importance, we can then ask if person B has a similar combination. What is important here is not the one-by-one counting of matches, but whether the whole pattern is replicated, or almost replicated, between two individuals (or groups).

What about the relation between genetic ancestry and individual phenotype? The authors do state that: “Thus it may be possible to infer something about an individual’s phenotype from knowledge of his or her ancestry.” However, since phenotypic traits are coded for by a number of genes smaller than that required to yield low genetic overlap, the authors assert that there may be significant phenotypic overlap between people of different groups. They give an example of a trait “determined by 12…loci,” which would yield a 36% overlap of phenotypes between individuals of different groups. Yet, racial groups show markedly different phenotypes. How is this so, if what the authors state is true? There are two points that the authors neglect to emphasize. First, many phenotypic traits, including racially relevant ones, have been selected for because of their adaptive value, or the populations commonly exhibiting these traits have been subject to genetic drift isolated from other populations. Thus, it is not reasonable to assume that genes that code for phenotype are going to have the same “worldwide distributions” as markers used in this study. For example, gene alleles coding for skin color show markedly higher frequency differences between populations than do the neutral markers used in population genetics. A second point is that racial phenotypes are the result of genetic structure, of many types of traits co-inherited together, and it is the sum total of all these differences that allow for racial distinction at the phenotypic level. Looking at individual phenotypic traits, just like looking at individual gene frequencies, is going to provide a markedly incomplete picture of human racial variation.

How do the findings of the paper relate to the subject of Frank Salter’s concept of “ethnic genetic interests?” This paper strongly supports the concept, which is dependent upon genetic differences between peoples. After all, there is essentially zero genetic overlap between individual members of the major racial groups; a member of one of these groups is always going to be more similar to a member of their own group than to that of another. Multiplied over the large numbers of people that constitute racial groups yields a very substantial genetic interest. Even if we take at face value this paper’s findings concerning the intermediate/admixed populations, the ethnic genetic interest concept holds as well. In the vast majority of cases, an individual will be more similar to members of their own group; overlap, while not zero, is low. When one multiples these differences over the large numbers of people involved, then there are very large and crucial differences of genetic interests regardless of which populations are considered.

But that is not all. First, consider that with sufficient numbers of genes assayed, the small degree of overlap observed with the intermediate/admixed groups may disappear; it would almost certainly disappear if genetic structure is considered. Second, and perhaps most important, the ethnic genetic interest concept is not based on overall genetic similarity/difference, but rather on differences in frequencies of distinctive genes, above and beyond random gene sharing. After all, those genes that do not differ in frequency between groups do not contribute to differences in genetic interests, because their frequency stays unchanged regardless of the outcome of competition. Even if an entire racial group were to die out, the frequency of these “shared genes” would remain unchanged. Note that measurements of overall genetic similarity, such as “w,” will as a matter of course also include genes that do not differ in frequency between groups. Therefore, even when “w” shows a low degree of overlap, there may well be no overlap at all with respect to those genes that are distinctive, that vary in frequency between populations.

To further explain the importance of distinctive genes vs. “w,” I will go back to my colored marbles analogy. Imagine that the distribution of colors for marbles 1-80 was completely random, but the colors for marbles 81-100 were specific to a person’s race. Overall similarity in marble color (analogous to “w”) would consider all 100 marbles. However, if we were to ask how the color frequencies of the marbles were to change if people of one race were completely removed from the example, we would observe that only marbles 81-100 would be affected. For marbles 1-80, since the color distribution is completely random with respect to race, it doesn’t matter if one race or another is eliminated from this marble counting exercise. Only the “population-distinctive marbles” are at issue here. Likewise, when considering competition and conflicting genetic interests between human groups, the gene frequencies that really matter are those that exhibit differences in frequency between the groups, not those that are randomly distributed between the groups.

Big Donger wrote on May 17^th, 2013 at 10:24am:


Did anyone ever think there was a single gene for 'race'?     Sounds like a strawman to me.

JC Denton wrote on May 17^th, 2013 at 5:27pm:


Sorry?  I am me.  Who do you think I am?   

Nobody needs a study to tell them there's such a thing as race when their own eyes will do. 

Genes cause a persons basic characteristics.  It's just simple cause & effect.