Geneticdiversitycomparisonof theDQA geneinEuropeanrabbit (Oryctolagus cuniculus) populations

The European rabbit (Oryctolagus cuniculus )n atu- ral populations within the species native region, the Iberian Peninsula, are considered a reservoir of genetic diversity. Indeed, the Iberia was a Pleistocene refuge to the species and currently two subspecies are found in the peninsula (Oryctolagus cuniculus cuniculus and Oryctolagus cuniculus algirus). The genes of the major histocompatibility complex (MHC) have been substantially studied in wild populations due to their exceptional variability, believed to be pathogen driven. Theyplayanimportant functionaspartofthe adaptive immunesystemaffecting the individualfitnessand population viability. In this study, the MHC variability was assessed by analysing the exon 2 of the DQA gene in several European rabbit populations from Portugal, Spain and France and in domestic breeds. Twenty-eight DQA alleles were detected, among which 18 are described for the first time. The Iberian rabbitpopulationsarewelldifferentiatedfromtheFrenchpop- ulation and domestic breeds. The Iberian populations retained the higher allelic diversity with the domestic breeds harbouring the lowest; in contrast, the DQA nucleotide diver- sity was higher in the French population. Signatures of posi- tive selection were detected in four codons which are putative peptide-binding sites and have been previously detected in other mammals. The evolutionary relationships showed in- stances of trans-species polymorphism. Overall, our results suggest that the DQA in European rabbits is evolving under selection and genetic drift