Empirical studies bear this logic out. The geneticist Hua Tang and his colleagues, for instance, found that self-reported ethnicity corresponded almost perfectly with genetic clusters from 326 microsatellite markers (a microsatellite marker is a piece of repetitive DNA in which a series of DNA base pairs are repeated). Other studies have demonstrated even more power to identify people’s ancestry accurately. These studies illustrate that, whatever the meaning of the claim that there is much more variation within than among races, researchers can, if they use the appropriate procedures, distinguish human ancestral groups from each other with remarkable accuracy. The significance of these genetic differences among groups is entirely an empirical question.
Most people believe that there are human races. They believe this not because they have a sophisticated understanding of genetic variation or human evolution, but because they see and categorize perspicuous phenotypic (and possibly behavioral) differences. Although many intellectuals have contended that these differences are largely superficial and distort underlying genetic realities, most research suggests that there are meaningful genetic differences among racial groups and that these differences are largely consistent with common racial classifications. Race is as real and useful as other constructs in the social sciences such as neuroticism, self-esteem, and intelligence. Therefore, with appropriate care and caution, scientists can and should study racial variation. This argument may appear alarming to people concerned about racial justice. But it doesn’t need to be. Tolerance and cosmopolitanism don’t require the leveling of diversity; they require the celebration of it. Race exists, but racism does not have to.