Race and genetics

The relationship between race and genetics is relevant to the controversy concerning race classification. In everyday life many societies classify populations into groups based on phenotypical traits and impressions of probable geographic ancestry and socio-economic status—these are the groups usually called "races" in countries like the United States. Because the patterns of variation of human genetic traits can be both abrupt and clinal, with a gradual change in trait frequency between population clusters, it is possible to statistically correlate clusters of physical traits with individual geographic ancestry. The frequencies of alleles tend to form clusters where populations live closely together and interact over periods of time. This is due to endogamy within kin groups and lineages or national, cultural or linguistic boundaries. This causes genetic clusters to correlate statistically with population groups when a number of alleles are evaluated.

In a similar way, genetic analysis enables us to determine the geographic ancestry of a person pinpointing the migrational history of a person's ancestors with a high degree of accuracy, and by inference the probable racial category into which they will be classified in a given society. In that way there is a distinct statistical correlation between gene frequencies and racial categories. However, because all populations are genetically diverse, and because there is a complex relation between ancestry, genetic makeup and phenotype, and because racial categories are based on subjective evaluations of the traits, it is not the case that there are any specific genes, that can be used to determine a person's race.

Most physical anthropologists consider race to be primarily a social category that does not correspond significantly with biological variation, but some anthropologists, particularly forensic anthropologists, consider race a useful biological category. They argue that it is possible to determine race from physical remains with a reasonable degree of certainty; what is identified is the geographic phenotype. Medical practitioners also sometimes argue that racial categories can be used successfully as proxies to assess risk of those different heritable illnesses that occur with different frequencies among populations of different geographic ancestries. Others argue that this use may be problematic because it risks underestimating risks of individuals from ethno-racial categories that are not considered high-risk, and to overestimate the risk in populations that are, resulting in stigmatization.

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