The African descent population of the Bananal community in the Brazilian state of Bahia (BA) was characterized as a genetic isolate and analyzed for some short tandem repeat (STR) microsatellite autosomic polymorphic loci (CSF1PO, TH01, TPOX, F13A1, FESFPS and vWA). These genetic variants were further compared to data obtained from an urban sample from the town of Jequié (BA) regarding demographic and anthropogenetic aspects. The Bananal sample comprised 32 unrelated individuals whereas Jequié was represented by 76 individuals. The Bananal Negroid Phenotypic Index (NPI) was 0.98 and the Negroid Cultural Index (NCI) 0.24. Consanguineous marriages occurred at a frequency of 34.61% and the F value was 0.0126. All six loci studied were in Hardy-Weinberg Equilibrium (p > 0.05). The genotypic and allele frequencies of the CSF1PO and vWA loci were similar. In the Bananal population the genic diversity of the THO1 locus was 66.8% and that of the F13A1 locus was 83.7%. The estimated ethnic racial admixture was 81% African and 19% Amerindian. The multiple correlation coefficient (R²) indicated adequate adaptation (99%). Total genetic variation for the six loci was 82.9% with an index of 6.7% for population subdivision (G ST' = 0.067). Anthropologic data and results obtained from the allele frequencies of the loci studied are indicative of a genetic isolate in Bananal, reminiscent of the a 'quilombo community' (i.e. one founded by run away slaves).
microsatellite; African-descendant isolate
