We studied human population structure using genotypes at 377 autosomal microsatellite loci in 1056 individuals from 52 populations. Within-population differences among individuals account for 93 to 95% of genetic variation; differences among major groups constitute only 3 to 5%. Nevertheless, without using prior information about the origins of individuals, we identified six main genetic clusters, five of which correspond to major geographic regions, and subclusters that often correspond to individual populations. General agreement of genetic and predefined populations suggests that self-reported ancestry can facilitate assessments of epidemiological risks but does not obviate the need to use genetic information in genetic association studies.
There is not a single race gene. Nor are all people in a race identical, so they don't have identical genetic profiles. But there is an abstract profile of what genes they are or are not likely to have, and these genes correspond to an evolutionary history of a species leaving Africa and becoming diverse.
In other words, genetics mirrors physical appearance and that recapitulates the evolutionary journey we have taken since being monkeys. This journey is complicated by overlapping interbreeding through history, such as the tendency of all racial groups to send some representatives back to Africa where they became bred into the population. Modern Africans are not what ancient Africans were; the north coast of Africa is mostly Caucasian in descent. Africa is the origin and returning point of human diversity.
However, this genetic alignment shows us several things:
- Our environments shaped us, we adapted characteristics, and now have abilities as a result. However, this depends on where your ancestors went.
- When we interbreed between ecotypes (ethnicity, race, tribe) the offspring have an initial period of vigor, but then settle into a lowest common denominator which can be found in abundance across the world.
- It is impossible to claim one race is superior over another, because each race/tribe/ethnicity has adapted to the conditions to which its environment subjected itself. Some ethnicities appear to have chosen conditions of a challenging nature that have endowed them with additional abilities. However, none of these abilities are objectively superior, an assessment that would require we first define a purpose.
Interesting research. We're doing race-related topics this week in preparation for our first half-black president.