Y-chromosome lineages in Sao Tome Principe Islands:: Evidence of European influence

The Y-chromosome haplogroup composition of the population of Sdo Tome e Principe (STP) archipelago was analyzed using 25 biallelic markers and compared with populations of different origins from Europe, Africa, and the Middle East. Two main Y-chromosome haplogroups were found: E3a, very common among sub-Saharans accounts for 84.2% of the paternal lineages and R1b, typical of West Eurasia, represents 8.7% of the overall male population. Nevertheless, we detected in the population of STP a significant heterogeneous distribution of Rlb among the two main ethnic groups of the archipelago: Forros (10.3%) and Angolares (6.6%). Together, haplogroups known to be prevalent in West Eurasia reach 12.5% of the chromosomes analyzed unequally distributed among the two groups: Forros present 17.7% while Angolares display only 8.2% of west Eurasian haplogroups. Our findings suggest that, despite its sub-Saharan genetic background, a relevant contribution of European paternal lineages is present in nowadays STP population. This influence has shown to be stronger in Forros than in Angolares, which could be explained by the social isolation that these have last experienced through their history.