Y haplogroup diversity of the Dominican Republic: reconstructing the effect of the European colonisation and the trans-Atlantic slave trades.

The Dominican Republic is one of the two countries on the Hispaniola island, which is part of the Antilles. Hispaniola was interested by the European colonisation and massive deportation of African slaves since the XVI century and these events heavily shaped the genetic composition of the present-day population. In order to shed light about the effect of the European rules, we analysed 92 SNPs on the Y chromosome in 182 Dominican individuals from three different locations. The Dominican Y haplogroup composition was characterised by an excess of northern African/European lineages (59%), followed by the African clades (38%), while the Native-American lineages were rare (3%). The comparison with the mtDNA variability, dominated by African clades, revealed a sex-biased admixture pattern, in line with the colonial society dominated by European men. When other Caribbean and non-Caribbean former colonies were also considered, we noted a difference between territories under a Spanish rule (like the Dominican Republic) and British/French rule, with the former characterised by an excess of European Y lineages reflecting the more permissive Iberian legislation about mixed people and slavery. Finally, we analysed the distribution in Africa of the Dominican lineages with a putative African origin, mainly focusing on central and western Africa, which were the main sources of African slaves. We found that most (83%) of the African lineages observed in Santo Domingo have a central African ancestry, suggesting that most of the slaves were deported from regions.