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The allele frequency distribution at the D1S80 locus (pMCT118) was analyzed in five Amerindian tribes from the Brazilian Amazon (Zoe, Awa-Guaja, Urubu-Kaapor, Katuena, and Xikrin of Bacaja) and was compared with distributions described for other worldwide populations. Nine different segregating alleles were identified in a sample of 139 individuals; alleles *18, *25, and *30 predominated in all tribes. Although the tribes are usually characterized by a low within-population diversity, they have a high interpopulational diversity, probably because of genetic drift acting on small isolated populations. Our data are similar to data for other Brazilian Amerindian tribes; these were combined for comparison with other human populations. Brazilian Amerindians are similar to the Pehuenche from Chile and to North American natives. However, the closest similarity was observed between Brazilian Amerindians and Polynesian populations (Samoans), probably reflecting common ancestry. Brazilian Amerindians and Asian populations have some similarities in terms of allele distribution (high frequencies of alleles *18 and *30), but the values of heterozygosity and the number of alleles are higher in Asians. Brazilian Amerindians are also clearly different from Europeans.