Adaptive molecular evolution of MC1R gene reveals the evidence for positive diversifying selection in indigenous goat populations

Detecting signatures of selection can provide a new insight into the mechanism of contemporary breeding and artificial selection and further reveal the causal genes associated to the phenotypic variation. However, the signatures of selection on genes entailing for profitable traits between Chinese commercial and indigenous goats have been poorly interpreted. We noticed footprints of positive selection at MC1R gene containing SNPs genotyped in five Chinese native goat breeds. An experimental distribution of FST was built based on approximations of FST for each SNP across five breeds. We identified selection using the high FST outlier method and found that MC1R candidate gene show evidence of positive selection. Furthermore, adaptive selection pressure on specific codons was determined using different codon based on maximum-likelihood methods; signature of positive selection in mammalian MC1R was explored in individual codons. Evolutionary analyses were inferred under maximum likelihood models, the HyPhy package implemented in the DATAMONKEY Web Server. The results of codon selection displayed positive diversifying selection at the sites were mainly involved in development of genetic variations in coat color in various mammalian species. Positive diversifying selection inferred with recent evolutionary changes in domesticated goat MC1R provides new insights that the gene evolution may have been modulated by domestication events in goats.