MTNR1A基因ExonⅡ T/C突变与绵羊季节性繁殖的关联性分析

Correlation between T/C mutation of MTNR1A gene ExonⅡ and seasonal reproduction of sheep

【目的】分析MTNR1A基因ExonⅡT/C突变与绵羊季节性繁殖性状的关联性,为深入研究MTNR1A基因在绵羊繁殖活动中的作用机制打下基础。【方法】以季节性繁殖的阿勒泰羊和中国美利奴羊(军垦型)及常年繁殖的湖羊和小尾寒羊为研究对象,采用PCR-SSCP及测序技术检测MTNR1A基因ExonⅡT/C突变在4个绵羊品种群体中的分布情况,并分析其与绵羊季节性繁殖性状的关联性。【结果】MTNR1A基因ExonⅡT/C突变致使MTNR1A蛋白的胞内无规卷曲结构域构象发生变化。在4个绵羊品种群体MTNR1A基因ExonⅡ处均可检测到T/C突变,其中阿勒泰羊和小尾寒羊中以TT基因型为主,T等位基因频率分别为C等位基因的3.4和11.2倍;在中国美利奴羊(军垦型)中则以TC基因型为主,TC基因型频率分别为TT和CC基因型的17.6和19.6倍;在湖羊中3种基因型的分布无明显差异。在阿勒泰羊群体中MTNR1A基因ExonⅡT/C突变位点处于Hardy-Weinberg平衡状态(P>0.05),而在中国美利奴羊(军垦型)、湖羊和小尾寒羊群体中处于极度不平衡状态(P<0.01)。【结论】在季节性繁殖的阿勒泰羊和中国美利奴羊(军垦型)及常年繁殖的湖羊和小尾寒羊群体MTNR1A基因ExonⅡ处均可检测到T/C突变,但该突变与绵羊的季节性繁殖性状无关联。

[Objective]The relationship of T/C mutation of MTNR1A gene ExonⅡand seasonal reproduction traits of sheep（Ovis aries） was investigated, in order to further research mechanism of MTNR1A gene in reproduction. [Method]Altay sheeps and Chinese Merino sheeps, which are seasonal estrous sheep breeds, Hu sheep and Small-tail Han sheep, which are perennial estrous sheep breeds, were chosen to detect distribution of T/C mutation of MTNR1A gene ExonⅡ in these four sheep breeds by PCR-SSCP and sequencing. [Result]The result showed that, T/C mutation of MTNR1A gene ExonⅡ could cause change of random coil conformation of MTNR1A protein. T/C mutation was detected in four sheep breeds, and TT was main genotype in Altay sheep and Small-tail Han sheep, allele frequencies of T were 3.4 and 11.2 times as those of C, respectively. But in Chinese Merino sheep population, TC was main genotype, its genotype frequency was as 17.6 and 19.6 times as those of TT and CC respectively. There was non-significant difference in Hu sheep popula-tion. T/C mutational site of MTNR1A gene ExonⅡ was in Hardy-Weinberg balance status in Altay sheep population（P〉0.05）, but was in extreme imbalance status in Chinese Merino sheep, Hu sheep and Small-tail Han sheep populations （P〈0.01）. [Conclusion]T/C mutation of MTNR1A gene ExonⅡ can be detected in Altay sheep and Chinese Merino sheep which are seasonal estrous sheep breeds, as well as Hu sheep and Small Tail Han sheep population which are perennial e-strous sheep breeds, but this mutation is not correlated with seasonal reproduction trait of sheep.