How well do self-identified ethnicity or “socially constructed racial categories” correspond to genetic reality?
Very well. For instance, Tang et al. assessed 326 microsatellite markers in 3,636 individuals from 15 different regions within the U.S. and Taiwan. Cluster analysis assigned all but 5 individuals to their self-identified ethnic group.17) We know that American Hispanics are usually mixes of some combination of Europeans, American Indians and black Africans, but still, dividing the data into 4 clusters produced a cluster, 99.8% of whose membership comprised of Hispanics. Genetic Cluster Analysis versus SIRE (self-identified race/ethnicity) CAU= white, AFR = black, HIS = Hispanic, CHI = Chinese, JAP = Japanese, OTH = other. In Cluster D, 8 of 9 individuals classified as “other” had self-identified as Hispanic. One may still object that different types of mulattos (black-white mixes) such as quadroons (one-fourth black), octoroons (one-eight black) and quintloons (one-sixteenth black) may all be classified as black even though their genetic affinities to whites and blacks are substantially
