As one of the most obvious phenotypic traits, the coat color of sheep is an ideal model to study the genetic mechanisms underlying coat color varieties of mammals. One distinguishable coat color is the black-headed type, such as the famous black-headed Dorper sheep from Africa and Bayinbuluke sheep from Asia. In this study, we compared the genome sequences of black-headed and all-white sheep to identify causative genes for the black-headed sheep, including black-headed Dorper vs. white-headed Dorper, as well as Bayinbuluke (black-headed) vs. Small-tailed Han (all-white). The most differentiating region between black-headed sheep and all-white sheep was found to harbor a haplotype covering melanocortin receptor 1 (MC1R) gene. The share of this haplotype by the black-headed sheep from Africa and Asia suggested that the convergent change in the MC1R region is likely to determine this unique coat color. Two missense mutations (g. 14251947T > A and g. 14252090G > A) within this haplotype of MC1R gene were found. We further analyzed whole genome sequence data of 460 worldwide sheep with diverse coat colors and confirmed the association between the MC1R haplotype with pigmentation variations. Our study provides novel insights into coat color genetics in sheep and expands our knowledge of the link between MC1R gene and varying pigmentation patterns in sheep.
Keywords: black-headed sheep; coat color; melanocortin receptor 1; missense mutations; sheep.
The diverse colors of sheep not only help to distinguish different breeds but also provide an ideal model to study the genetics underlying mammalian coat color variations. One unique coat color in sheep is the black-headed type, as represented by the famous meat breed Dorper sheep from Africa and Bayinbuluke sheep from Asia. In this study, we compared the genomes of black-headed sheep with all-white sheep in order to identify genes responsible for this distinguishable coat color. By analyzing genomic selection signals and haplotypes, we located MC1R as the most likely causative gene determining the black-headed coat color in sheep. Our study expanded our understanding of the genetic mechanisms of coat color diversities in sheep.
© The Author(s) 2023. Published by Oxford University Press on behalf of the American Society of Animal Science.