Evolution of the melanocortin-1 receptor gene (MC1R) in chamois (Rupicapra spp.)

The taxonomy of chamois and the effects of historical and evolutionary events on its diversification are still under discussion given that different morphological and genetic features presented partially discordant views. One of the morphological features that differentiate the two currently considered species, Rupicapra pyrenaica (southern chamois) and R. rupicapra (northern chamois) is coat color pattern. The melanocortin-1 receptor gene (MC1R) is related with differences in coloration in different mammals and was analyzed here in a sample of 25 chamois covering the 10 subspecies recognized, three in R. pyrenaica, (parva, pyrenaica and ornata) and seven in R. rupicapra (cartusiana, rupicapra, tatrica, carpatica, balcanica, asiatica and caucasica). Comparison with other caprinae showed that the MC1R gene has evolved under strong purifying selection. Three well differentiated haplotypes were identified: one shared by the seven subspecies of R. rupicapra, other common to the two Iberian chamois, both of the species R. pyrenaica, and a third haplotype, basal in the phylogenetic tree, unique to the subspecies from the Apennines, R. pyrenaica ornata. This pattern of variation, with three conspicuous clades, concurs with previous findings on microsatellites and mtDNA and argues in favor of the old classifications that distinguished the species R. ornata.