Y-chromosome and surname analysis of the native islanders of San Andrés and Providencia (Colombia).

The Archipelago of San Andrés and Providencia is a Colombian Department in the western waters of the Caribbean Sea. Most of its inhabitants belong to the African-Colombian group known as raizal. This group has unique cultural traits that are derived from centuries of admixture of the primarily African slaves and European colonists. Currently, not much is known about the genetic profile of this population. Therefore, this study aimed to determine the Y-chromosome STR genetic structure and relationship to previously published reference populations. A total of 54 natives from the islands were selected based on the genealogical criterion of having three generations of ancestors born in the Archipelago. Seventeen Y-STRs were analyzed, supplemented by information on the first surname inherited. The genetic substructure hypothesis in the studied islands was tested, and no significant differences were found (p>0.05). Y-chromosome haplogroups were predicted, and E1b1a and R1b were the most commonly found haplogroups. They account for more than 80% of the sample. The E1b1a and R1ba haplogroups are common in the African and European populations, respectively. For comparative genetic analysis, genetic distances were calculated with respect to populations from the Caribbean, Colombia, Europe and Africa. We found greater similarity between the African and Caribbean populations. The surname analysis demonstrated that most of the time, the "raizales" with the same surname also shared the same Y-STR haplotype. This suggests that some kinship relationship exists between participants with the same surname, which was confirmed by the haplotype diversity levels found in the studied islands.