SHORT TANDEM REPEAT POLYMORPHISM EVOLUTION IN HUMANS

Forty-five dinucleotide short tandem repeat polymorphisms were typed i n ten large samples of a globally distributed set of populations. Alth ough these markers had been selected for high heterozygosity in Europe an populations, we found them to be sufficiently informative for linka ge analysis in non-Europeans. Heterozygosity, mean number of alleles, and mean number of private alleles followed a common trend: they were highest in the African samples, were somewhat lower in Europeans and E ast Asians, and were lowest in Amerindians. Genetic distances also ref lected this pattern, and distances modelled after the stepwise mutatio n model yielded trees that were less in agreement with other genetic a nd archaeological evidence than distances based on differentiation by drift (F-ST). Genetic variation in nonAfricans seems to be a subset of that in Africans, supporting the replacement hypothesis for the origi n of modern humans.