College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China.
J Anim Sci. 2023 Jan 3;101. doi: 10.1093/jas/skad084.
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.
作为最明显的表型特征之一，绵羊的毛色是研究哺乳动物毛色多样性遗传机制的理想模型。一种可区分的毛色是黑头类型，例如来自非洲的著名黑头德克塞尔羊和来自亚洲的巴音布鲁克羊。在这项研究中，我们比较了黑头羊和全白羊的基因组序列，以鉴定导致黑头羊毛色的候选基因，包括黑头德克塞尔羊与白头德克塞尔羊，以及巴音布鲁克羊（黑头）与小尾寒羊（全白）。在黑头羊和全白羊之间，最具区分性的区域被发现含有一个覆盖黑素皮质素受体 1（MC1R）基因的单倍型。来自非洲和亚洲的黑头羊共享这个单倍型，这表明 MC1R 区域的趋同变化可能决定了这种独特的毛色。在 MC1R 基因的这个单倍型中发现了两个错义突变（g.14251947T > A 和 g.14252090G > A）。我们进一步分析了来自世界各地 460 只具有不同毛色的绵羊的全基因组序列数据，并证实了 MC1R 单倍型与色素沉着变化之间的关联。我们的研究为绵羊毛色遗传学提供了新的见解，并扩展了我们对 MC1R 基因与绵羊不同色素沉着模式之间联系的认识。
