Genetic diversity of wild boar populations and domestic pig breeds (Sus scrofa) in south-western Europe

The Eurasian wild boar, Sus scrofa, is an important game species and is widely distributed in Eurasia. The recent demographic expansions allied to man mediated translocations and reintroductions, reshaped the genetic variability of wild boar populations, and gave rise to management problems. Genetic variability and the population structure of the European populations are not well-known, in particular in the Iberian Peninsula. In the present study, we assessed the phylogenetic relationship among 17 Iberian wild boar populations and several Eurasian wild and domestic pigs by sequencing 660 bp of the mitochondrial (mt)DNA control region. This analysis was extended to the two autochthonous Portuguese pig breeds, Bísaro and Alentejano, and their relationship with Eurasian pigs was also established. High levels of gene diversity were found in Iberian wild boar and Portuguese domestic pigs, as well as a significant genetic difference among and within populations. Iberian wild boar and Portuguese pig breeds belong to the main European clade but diverge with animals from Central Europe, showing a high proportion of private (Iberian) haplotypes. These results suggest the existence of glacial refugia for Sus scrofa in the Iberian Peninsula during the Last Glacial Maximum. No signs of Asian mtDNA introgression from Asian populations were found in the present survey.