Genetic Differentiation of the Cabo Verde Archipelago Population Analysed by STR Polymorphisms

Allele frequencies for 17 STR loci were analyzed in a sample of unrelated males from the Cabo Verde Archipelago. The samples were gathered in such a way that the origin of the subjects was perfectly identified, and they could be included in one of the leeward or windward groups of islands. This study reveals that there are significant differences between both groups of islands, and between Cabo Verdeans and other populations from sub-Sahara Africa including the Guineans, the most probable source population for Cabo Verdeans. This study confirms mtDNA data and, together with HLA and Y chromosome data already published, shows that the Cabo Verde population is substructured and atypical, diverging substantially from mainland sub-Saharan populations. Overall these differences are most probably due to admixture between sub-Saharan slaves brought into the islands and other settlers of European origin. In the absence of a clear indication of a different ethnic composition of the first sub-Saharan settlers of Cabo Verde, the differentiation exhibited in both groups of islands can be most probably be attributed to genetic drift.

In recent years we have seen an exponential increase of STR (Short Tandem Repeat) data, usually presented as allele frequencies that may be later used as databases for forensic and population genetics purposes (Holt et al. 2000, and see references therein). Differences in STR allele frequencies among populations can correctly reveal their genetic relationships in those cases where collection samples are properly gathered, and only then do genetic profiles really represent the populations under study.We present a population study of Cabo Verdeans, where subjects were chosen in such a way that the families of both parents were natives from the same island for at least three generations. In this way we tried to obtain a genetic profile that minimizes the effect of recent population movements between the islands belonging to the archipelago of Cabo Verde.