Diversity and evolution of the Mhc-DRB1 gene in the two endemic Iberian subspecies of Pyrenean chamois, Rupicapra pyrenaica

Major histocompatibility complex class II locus DRB variation was investigated by single-strand conformation polymorphism analysis and sequence analysis in the two subspecies of Pyrenean chamois (Rupicapra pyrenaica) endemic to the Iberian Peninsula. Low levels of genetic variation were detected in both subspecies, with seven different alleles in R. p. pyrenaica and only three in the R. p. parva. After applying the rarefaction method to cope with the differences in sample size, the low allele number of parva was highlighted. The low allelic repertoire of the R. p. parva subspecies is most likely the result of bottlenecks caused by hunting pressure and recent parasitic infections by sarcoptic mange. A phylogenetic analysis of both Pyrenean chamois and DRB alleles from 10 different caprinid species revealed that the chamois alleles form two monophyletic groups. In comparison with other Caprinae DRB sequences, the Rupicapra alleles displayed a species-specific clustering that reflects a large temporal divergence of the chamois from other caprinids, as well as a possible difference in the selective environment for these species.