促性腺激素释放激素受体(GnRHR)基因多态性及其与山羊产羔数的相关性分析

摘要

本研究采用候选基因法对与繁殖性能有关的遗传标记进行筛选,旨在为山羊高产仔数的标记辅助选择提供确切的遗传依据.参考牛的促性腺激素释放激素受体(Gonadotropin releasing hormone receptor,GnRHR)基因序列设计4对引物,采用聚合酶链式反应-单链构象多态性(PCR-SSCP)技术检测GnRHR基因在波尔山羊以及我国西南地区9个地方山羊品种中的单核苷酸多态性(Single nucleotide polymorphism,SNP),同时在川东白山羊、古蔺马羊和贵州白山羊3个群体中研究该基因多态性与山羊产仔数之间的相关性.结果显示,4对引物中只有引物P1扩增片段检测出多态性.对于P1的扩增片段,在不同的山羊品种中检测到AA、GG和AG 3种基因型,测序分析表明GG与AA型相比有一处单碱基突变(154G→A).AA基因型个体在3个群体中产羔数最小二乘均值都显著高于GG和AG基因型个体(P＜0.05),GA基因型个体在古蔺马羊中的产羔数显著高于GG型个体(P＜0.05),而在其它2个品种中差异不显著(P＞0.05).本研究结果初步表明山羊GnRHR基因的突变与其繁殖性能有关,可能是影响山羊繁殖率的一个因素.%The objectives of the present study were to search for genetic markers associated with high prolificacy by candidate gene approach and to give a scientific genetic basis for marker-assisted selection for high reproductivity in goats. According to the Bos taurus GnRHR gene sequence, four pairs of primers were designed to detect single nucleotide polymorphisms of GnRHR gene in Boer and other nine breeds of goats in southwest China by PCR-SSCP. The relationship between the polymorphism of GnRHR gene and litter size was observed in Chuandong White goat, Gulin Ma goat and Guizhou White goat. Only the sequences amplified by primers PI showed polymorphisms. Genotypes (AA, AG and GG) were detected in different goat breeds. The sequencing results revealed that the genotype GG had one mutation (154G→A) compared to AA genotype.The goats with genotype AA have significant higher litter size than those with genotype GG and AG in three breeds of goats (P<0. 05). And the goats with genotype GA were higher than those with genotype GG (P<0. 05) in Gulin Ma goat. The finding showed that the GnRHR gene was related to the prolificacy of goats, which may be a factor affecting the reproduction in goats.