Evidence for population sub-structuring in Sao Tome e Principe as inferredfrom Y-chromosome STR analysis

Seven Y-chromosome STR loci, DYS19, DPS389I, DYS389II, DYS390: DYS391, DYS3 92 and DYX393 have been analysed in population samples of Angolares, Forros and Tong as; three ethnic groups from the African archipelago of Sao Tome e Principe (Gulf of Guinea). Complete typings were obtained for 103 chromos omes, which belonged to 79 different haplotypes. The mean heterozygosity pe r locus in the overall Sao Tomean sample was 0.566, with the highest value found among Forros and the lowest among Angolares. Angolares also showed th e lowest level of haplotype diversity. On average, the mean pairwise differ ence between two random haplotypes from Angolares, Forros and Tongas was 4. 69, 6.74 and 6.23 repeats, respectively. The genetic distances were found t o be statistically significant between Angolares and Forros or Tongas. In a ccordance, AMOVA revealed that the percentage of variation attributable to differences among groups was only significant when we distinguished between Angolares and non-Angolares. Globally, these results indicate that, with r espect to the pool of male lineages of Sao Tome e Principe, some genetic su b-structuring does exist, basically determined by the Angolares ethnic grou p.