Variability of the F13B locus in South American populations.

A population study for the F13B locus was carried out in a total of 396 South American individuals. The analysis comprised new data from 5 Amerindian populations, existing data from 3 Amerindian populations, and I urban sample from La Plata, Argentina. In both pooled Amerindian and La Plata samples, 6 alleles were found. The individual Amerindian samples showed a lower number of alleles, changes in modal alleles, and restricted variability. Interpopulation comparisons revealed significant differences among samples from distinct geographical regions. Differences among the groups were also corroborated by the F(ST) statistic. Data support the hypothesis that genetic drift and gene flow influence Amerindian differentiation.