牛黑素皮质素受体1(MC1R)基因与毛色表形的研究

牛MC1R基因不仅与毛色有关, 而且与牛乳中乳蛋白的含量有关。利用PCR-RFLP和DNA测序技术分析了中国荷斯坦黑白花牛, 中国荷斯坦红白花牛, 鲁西黄牛和渤海黑牛共4个品种的MC1R基因。共检测出3种等位基因(E^D, E⁺, e)。中国荷斯坦黑白花牛主要是E^D和E⁺等位基因(E^D=0.12、E⁴=0.80); 渤海黑牛也主要是E^D和E⁺等位基因(E^D=0.52、E⁺=0.47); 中国荷斯坦红白花牛和鲁西黄牛大多为e等位基因(e=0.95)。中国荷斯坦红白花牛和鲁西黄牛还存在E⁺/e基因型。由此推测E^D和E⁺等位基因导致黑色素合成。另外发现牛MC1R基因编码区725处存在一重要的SNP(单核苷酸多态性)。

Relationship between the melanocortin receptor 1 (MC1R) gene and the coat color phenotype in cattle

The MC1R gene is related to coat color in cattle and to lactoprotein content in milk. Polymerase chain reaction-restriction fragment length polymorphism and DNA sequencing were used to analyze the MC1R of China Holstein Black-white Cattle, China Holstein Red-white Cattle, Luxi Yellow Cattle and Bohai Black Cattle. Three alleles (E^D, E⁺ and e) were identified. Most China Holstein Black-white Cattle had E^D and E⁺ alleles (E^D = 0.12, E⁺ = 0.80). The same was true for Bohai Black Cattle (E^D = 0.52, E⁺ = 0.47). On the other hand, most China Holstein Red-white Cattle and Luxi Yellow Cattle had the e allele (e/e = 0.95). E⁺/e genotype was present in China Holstein Red-white Cattle and Luxi Yellow Cattle. We reasoned that E^D and E⁺ lad to the synthesis of the black pigment. Furthermore, we found an important SNP (Single Nucleotide Polymorphism) at 725 position of the MC1R coding region.