绵羊ESR2基因组织表达及其多态性与产羔数关联分析

为了探究雌激素受体2 (Estrogen receptor 2, ESR2)基因在绵羊各组织的表达及其多态性与产羔数之间的关系,本研究利用半定量PCR和实时荧光定量PCR技术检测ESR2基因在不同繁殖力小尾寒羊群体组织中的相对表达量,同时采用Sequenom MassARRAY誖SNP技术对多羔品种绵羊(小尾寒羊,湖羊,策勒黑羊)和单羔品种绵羊(苏尼特羊,草原型藏羊,滩羊) ESR2基因g.73324006C>T位点进行检测,并与小尾寒羊产羔数进行关联分析。半定量PCR表明,ESR2基因在单、多羔小尾寒羊子宫中高表达,在其它组织中等或低丰度表达;单羔群体、多羔群体间荧光定量PCR表明,ESR2基因在单羔小尾寒羊垂体表达量显著高于多羔小尾寒羊(p<0.05);群体遗传学分析表明,g.73324006C>T在小尾寒羊群体中表现为低度多态(PIC<0.25),在滩羊群体中处于中度多态(0.25T在小尾寒羊群体处于哈代温伯格平衡状态(p>0.05);关联分析表明,g.73324006C>T位点多态性与小尾寒羊第一胎、第二胎、第三胎产羔数及平均产羔数均显著关联(p<0.05),CC型各胎产羔数均高于TC型。与FecB (A746G)基因组合后发现,GG-CC和AG-CC基因型母羊产羔数显著高于AA-TC、AA-CC、AG-TC基因型组合(p<0.05)。综上,ESR2与小尾寒羊产羔数密切相关,g.73324006C>T可作为绵羊产羔性状选育的潜在分子标记。

Tissue Expression and Polymorphism of Sheep ESR2 Gene and Their Associations with Litter Size

To elucidate the association between tissue expression and polymorphism of ESR2 and litter size in sheep,semi-quantitative RT-PCR and qPCR were performed to investigate the expression of ESR2 gene in multiparous Small Tail Han sheep and uniparous Small Tail Han sheep.Multiparous(Small Tail Han sheep,Hu sheep,Cele black sheep)and uniparous(Sunite,Tan sheep,Prairie Tibetan sheep)sheep breeds were selected and Sequenom MassARRAYSNP assay was applied to genotype g.73324006 C>T loci of ESR2 gene.Then the association was analyzed between ESR2 and litter size in Small Tail Han sheep.The results of semi-quantitative RT-PCR revealed that ESR2 had high level in uterus in both uniparous and multiparous sheep,and had moderate or low level in other tissues.The results of qPCR showed that the expression of ESR2 was higher in pituitary of uniparous Small Tail Han sheep than in multiparous sheep(p<0.05).Population genetic analysis indicated that g.73324006 C>T was moderate polymorphism(0.25T was under Hardy-Weinberg equilibrium(p>0.05)in Small Tail Han sheep.The association analysis result indicated that the polymorphism of g.73324006 C>T had correlation with the litter size of the first,second and third parity in Small Tail Han sheep(p<0.05),while the litter size of CC was higher than CT for each parity.The combination of ESR2 gene g.73324006 C>T and FecB(A746 G)gene showed that the number of lambs in GG-CC and AG-CC genotypes was significantly higher than that of AA-TC,AA-CC and AG-TC genotypes(p<0.05).Therefore,it can be concluded that ESR2 may be the key gene for litter size and the g.73324006 C>T loci might provide a basis for litter size trait selection in sheep.