Diversity of two short tandem repeat loci (CD4 and F13A1) in three Brazilian ethnic groups

Two microsatellites (CD4 and F13A1) were investigated in seven Brazilian po pulations: one group each of European- and African-derived subjects from Po rto Alegre, southern Brazil, and five Amerindian tribes (three Tupi-Monde s peaking [Gaviao, Surui, and Zoro], one Macro-Ge [Xavante], and one Carib [W ai-Wai]). For both markers, neo-Brazilians presented with a high diversity, but Amerindians showed a low level of variability. Genotype frequency dist ributions were heterogeneous among populations, the only exception being si milar CD4 frequencies in Afro- and Euro-Brazilians. Gene diversity analysis revealed that most of the total variation is due to intrapopulational dive rsity in all populations, Because of the high information content of these markers in Afro- and Euro-Brazilians, these systems are most appropriate fo r forensic analyses. The comparison among Brazilian and other world populat ions revealed high similarity among populations of the same ethnic group, i ndicating a high discriminative power for these markers.