Genetic diversity of two African and sixteen South American populations determined on the basis of six hypervariable loci

A total of 582 individuals (1,164 chromosomes) from two African, eight Afri can-derived South American, five South American Amerindian, and three Brazi lian urban populations were studied at four variable number of tandem repea t (VNTR) and two short tandem repeat (STR) hypervariable loci. These two se ts of loci did not show distinct allele profiles, which might be expected i f different processes promoted their molecular differentiation. The two Afr ican groups showed little difference between them, and their intrapopulatio nal variation was similar to those obtained in the African-derived South Am erican communities. The latter showed different degrees of interpopulation variability, despite the fact that they presented almost identical average degrees of non-African admixture. The F-ST single locus estimates differed in the five sets of populations, probably due to genetic drift, indicating the need to consider population structure in the evaluation of their total variability. A high interpopulational diversity was found among Amerindian populations in relation to Brazilian African-derived isolated communities, This is probably a consequence of the differences in the patterns of gene f low and genetic drift that each of these semi-isolated groups experienced. (C) 1999 Wiley-Liss, Inc.