Lewontin’s Fallacy — which primarily concerns the amount and importance of genetic difference between regional populations — has caused so much mischief that it can’t be debunked enough.
Here is Long (2010) on it:
Earlier in this decade, Rick Kittles and I took an unusually critical look at FST (Long and Kittles 2003). We analyzed a unique data set composed of short tandem repeat (STR) allele frequencies for eight loci genotyped in both humans and chimpanzees (Deka et al. 1995). These data made it possible to see how FST played out when no one could dispute taxonomic and genetic significance. The answer surprised us. FST was pretty close to the canonical 0.15 shown so many times for human populations. In our analysis, FST was 0.12 for humans, but for humans and chimpanzees together, FST rose only to 0.18. Indeed, we found one locus, D13S122, where the size range of human and chimpanzee alleles hardly overlapped, yet FST equaled 0.15 (Figure 1)….
…Richard Lewontin’s dismissal of race may not have led to the wide popularity of FST in population biology, but it did galvanize anthropology. Lewontin confronted race by trying to show that classical racial groupings accounted for too little of the total diversity to be of any value. In retrospect, it is odd that Lewontin felt that 15% of variation among groups is small and even odder that others have concurred. Sewall Wright, the inventor of FST , believed the opposite. To Wright, FST = 0.05 or even less indicates considerable differences, and FST = 0.15 reflects moderately great differences (Wright 1951, 1978). Low values of FST reflect large gene frequency differences in replicate populations (Figure 2). In other words, these seemingly small values of FST permit allele frequencies to drift widely among populations. Unfortunately, Lewontin did not contest the larger issue, which is whether or not races are a good way to portray the pattern of gene frequency differences between populations.
Long goes onto argue that the classically defined races don’t represent subspecies. Whether they do or not, though, depends on the definition employed; and the issue is largely academic. The important point is that Lewontin’s widely adopted interpretation of Fst values that lent to the widespread belief in insignificant genetic differences between populations has been thoroughly debunked. This interpretation now has been shown to be fallacious on a number of accounts.
It may be that “human genetic equality is a contingent fact of history,” as Gould argued, stating:
Human groups do vary strikingly in a few highly visible characters (skin color, hair form) — and this may fool us into thinking that overall differences must be great. But we now know that our usual metaphor of superficiality — skin deep — is literally accurate. (Gould, 1984. Human equality is a contingent fact of history.)
But studies of within-between group variability do not provide evidence for this as Gould and others thought. The traits that to Gould’s mind defined human worth will have to be analyzed one by one to see if in fact human populations are equal, as so understood.
Long, 2010. Update to Long and Kittles’s “Human Genetic Diversity and the Nonexistence of Biological Races”(2003): Fixation on an Index