棕背伯劳羽色多态与MC1R基因的相关性

黑素皮质素受体1 (melanocortin-1 receptor, MC1R)基因是控制动物黑色素合成的重要基因, 鸟类羽色的变异与MC1R基因的变异有密切关系。棕背伯劳(Lanius schach)在我国东部沿海多地存在羽色多态现象, 有棕色型、黑色型和黑色白边型的分化。为了探究MC1R基因与棕背伯劳色型分化的关系, 本研究对分布于广东省的3种色型共计11只棕背伯劳的MC1R基因编码区进行单核苷酸多态性(SNPs)分析和氨基酸多态性分析。结果表明: (1) 11个实验个体的MC1R基因序列共有4种单倍型, 其中黑色型和黑色白边型共享单倍型H3。(2) 3种色型棕背伯劳MC1R基因编码区的第34-931位的899个碱基中共有47个碱基变异位点, 相对应的氨基酸序列共有18个变异位点, 这些变异位点与黑色表型无对应关系。(3)黑色型与黑色白边型个体基因型在第268-303位编码区出现了36个碱基的缺失, 对应着12个氨基酸的缺失, 该缺失与黑色表型相对应。因此推测棕背伯劳的黑化与MC1R基因碱基片段的缺失密切相关。

Correlation between color polymorphism and the MC1R gene of Lanius schach

MC1R (melanocortin-1 receptor) is an important gene that controls melanin synthesis in animals. The variation of plumage color in birds is closely related to variation in the MC1R gene. Lanius schach exhibits color polymorphism that differentiates into brown, black, and white-remiged black morphs in many provinces along the east coast of China. In order to explore the relationship between genetic variation in MC1R and color polymorphism in Lanius schach in Guangdong, single nucleotide polymorphisms (SNPs) and amino acid polymorphisms in the coding region of the MC1R gene were analyzed in 11 Lanius schach individuals of three different color types. The results showed: (1) A total of 4 haplotypes in the MC1R gene sequences of 11 individuals, among which the black morphs and the white-remiged black morphs shared haplotype H3; (2) There were 47 base mutations in 899 bases of the coding region (34-931), and the corresponding amino acid sequence had a total of 18 mutation sites. These mutation sites did not correspond to the black phenotype; (3) The deletion of 36 bases in the 268-303 coding region of the black morph and the white-remiged black morph individual genotypes, resulting in the deletion of 12 amino acids. This deletion corresponded to the black phenotype. Therefore, we speculate that the melanism of Lanius schach is closely related to the deletion of the base fragment of the MC1R gene.