促性腺激素释放激素受体(GnRHR)基因多态性及其与济宁青山羊高繁殖力关系

设计8对引物, 应用聚合酶链式反应-单链构象多态性（PCR-SSCP）技术检测促性腺激素释放激素受体（gonadotropin releasing hormone receptor, GnRHR）基因外显子1、外显子2和外显子3在高繁殖力山羊(Caprar hircus)品种（济宁青山羊）和低繁殖力山羊品种（安哥拉、波尔和内蒙古绒山羊）中的单核苷酸多态性，同时研究该基因对济宁青山羊高繁殖力的影响。结果发现引物P4扩增片段具有多态性，其余7对引物的扩增片段都不存在多态性。对于引物P4扩增片段，在济宁青山羊、波尔山羊和内蒙古绒山羊中均检测到AA、AB和BB基因型，而在安哥拉山羊中只检测到AA和AB基因型，未检测到BB基因型；测序分析发现BB型与AA型相比在外显子1有1个突变（757G→A），但未引起氨基酸改变；济宁青山羊AA、AB和BB基因型频率分别为0.623、0.300和0.077，BB型济宁青山羊平均产羔数比AB型和AA型分别多0.69只（P　<　0.05）和0.82只（P　<　0.05），AA型和AB型济宁青山羊产羔数的最小二乘均值差异不显著（P　>　0.05）。

Polymorphism of Gonadotropin Releasing Hormaone Receptor (GnRHR) Gene and Its Relationship with Prolificacy of Jining Grey Goat

The gonadotropin releasing hormone receptor (GnRHR) gene was studied as a candidate gene for the high prolificacy of Jining grey goat(Caprar hircus). Eight pairs of primers were designed to detect single nucleotide polymorphisms of exon 1, exon 2 and exon 3 of GnRHR gene in high fecundity breed(Jining grey goat) and low fecundity breeds(Angora, Boer and Inner Mongolia Cashmere goats) by PCR-SSCP. Only the products amplified by primer P4 displayed polymorphisms. For primer P4, three genotypes (AA, AB and BB) were detected in Jining grey, Boer and Inner Mongolia Cashmere goats, only AA and AB genotypes were in Angora goats. Sequencing revealed one mutation (757G→A) of exon 1 in genotype BB compared with genotype AA, which did not cause amino acid changes. In Jining Grey goats, frequency of AA, AB and BB genotypes was 0.623, 0.300 and 0.077, respectively. The Jining grey with genotype BB had 0.69(P < 0.05) or 0.82(P < 0.05) kids, more than those with AB or AA, respectively. The difference of the least squares means for litter size between AA and AB was nonsignificant (P > 0.05) in Jining grey goat.