Nucleotide diversity of the melanocortin 1 receptor gene (MC1R) in the gayal (Bos frontalis)

The melanocortin 1 receptor gene (MC1R) plays a crucial role in determining coat colour of mammals. To investigate the relationship of polymorphism of the MC1R with coat colour in gayal, the coding sequence (CDS), and the 5'- and 3'-untranslated regions (UTR) of the MC1R were sequenced from 63 samples from the gayal and compared with the sequences of the MC1R from other ruminant species. A sequence of 1,136 bp including the whole CDS (954 bp) and parts of the 5'- and 3'-UTR (164 and 18 bp, respectively) of the gayal MC1R was obtained. A total of nine single nucleotide polymorphisms (SNPs) including four SNPs (c.-129T > C, c.-127A > C, c.-106C > T, c.-1G > A) in the 5'-UTR and five SNPs (c.201C > T, c.583C > T, c.663T > C, c.871A > G and c.876T > C) in the CDS were detected, revealing high genetic diversity. Three novel coding SNPs including c.201C > T, c.583C > T and c.876T > C, which have not been reported previously in bovid species, were retrieved. Within five coding SNPs, c.201C > T, c.663T > C and c.876T > C were silent mutations, while c.583C > T and c.871A > G were mis-sense mutations, resulting in changes in the amino acids located in the fifth (p.L195F) and seventh (p.T291A) transmembrane regions, respectively. The alignment of amino acid sequences was found to be very similar to those for other bovid species. It was demonstrated, using the functional effect prediction, that the p.T291A amino acid replacement could have an effect on MC1R protein function but not for the p.L195F substitution. Using phylogenetic analyses it was revealed that the gayal has a close genetic relationship with the yak. However, three classical bovine MC1R loci the E (D) , E (+) and e were not retrieved in the gayal, indicating other genes or factors could affect coat colour in this species.