Isolation and characteristics of the melanocortin 1 receptor gene (MC1R) in the Chinese yakow (Bos grunniens×Bos taurus)

The Chinese yakow is the offspring of yak (Bos grunniens) and Yellow cattle (Bos taurus). The melanocortin 1receptor 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 the Chinese yakow, the coding sequence (CDS) and the flanking region of MC1R were sequenced from 84 Chinese yakow samples and compared with the sequences of the MC1R from other bovid species. A fragment of 1134 base pair (bp) sequences including the full CDS (954bp) and parts of the 5'- and 3'-untranslated regions (162 and 18bp, respectively) of the Chineseyakow MC1R were obtained. A total of 13 single nucleotide polymorphisms (SNPs) including 4 SNPs (T-129C, A-127C, C-106T, G-1A) in the 5'-untranslated region and 9 SNPs (C201T, T206C, C340A, C375T, T663C, G714C, C870T, G871A and T890C) in the CDS were identified, revealing high genetic variability. Four novel SNPs including T206C, G714C, C870T and T890C, which have not been reported previously in bovid species, were retrieved. Within 9 coding SNPs, C201T, C375T, T663C and C870T were silent mutations, while T206C, C340A, G714C, G871A and T890C were mis-sense mutations, corresponding to amino acid changes p.L69P, p.Q114K, p.K238N, p.A291N and p.I297T, respectively. Amino acid sequences alignment showed a more than 96% similarity with other ruminates. However, three classical bovine MC1R loci the E(D), E(+) and e were not retrieved in the Chinese yakow, indicating other genes or factors could be involved in affecting coat colour in this species.