小尾寒羊BMP15基因多态性及其与高繁殖力关系的研究

以控制Belclare、Cambridge、Hanna、Inverdale和Lacaune绵羊高繁殖力的骨形态发生蛋白15基因(bonemorpho-geneticprotein15,BMP15)为候选基因,根据绵羊BMP15基因全序列设计6对引物覆盖全部的外显子,采用PCR-SSCP方法检测BMP15基因在高繁殖力绵羊品种(小尾寒羊)和低繁殖力绵羊品种(多赛特羊)中的多态性,同时研究该基因对小尾寒羊高繁殖力的影响。结果表明,只有外显子1的第1对引物扩增片段具有多态性,其余5对引物扩增片段都没有多态性。在127只小尾寒羊母羊和30只多赛特母羊中都检测到两种基因型(AA和AB)。统计结果表明,小尾寒羊和多赛特羊AA基因型频率分别为0.638和0.800,AB基因型频率分别为0.362和0.200。测序结果表明,AB基因型和AA基因型相比在cDNA第28bp处缺失了3个碱基(CTT),小尾寒羊和多赛特绵羊都发生了与Belclare、Cambridge、Hanna和Inverdale绵羊相同的CTT缺失突变。AB基因型小尾寒羊平均产羔数比AA基因型多0.20只,但差异不显著(P>0.05)。研究结果提示,BMP15基因的CTT缺失突变对小尾寒羊高繁殖力没有显著影响。

Polymorphism of BMP15 Gene and Its Relationship of Prolificacy of Small Tail Han Sheep

The bone morphogenetic protein 15 gene(BMP15) which controls the fecundity of Belclare, Cambridge, Hanna, Inverdale and Lacaune ewes was studied as a candidate gene for the prolificacy of Small Tail Han sheep. According to the sequence of ovine BMP15 gene, six pairs of primers were designed to detect single nucleotide polymorphisms of exon 1 and exon 2 of BMP15 gene in both high fecundity breed (Small Tail Han sheep) and low fecundity breed (Dorset sheep) by PCR-SSCP. Two pairs of primers (primer 1-1 and primer 1-2) were used to amplify the exon 1. Four pairs of primers (primer 2-1, primer 2-2, primer 2-3 and primer 2-4) were used to amplify the exon 2. Only the products amplified by primer 1-1 were displayed polymorphism. Two genotypes (AA and AB) were detected in both sheep breeds. In Small Tail Han sheep and Dorset sheep, frequency of genotype AA was 0.638 and 0.800, frequency of genotype AB was 0.362 and 0.200, respectively. Sequencing revealed a CTT deletion mutation at 28~30 bp of exon 1 of BMP15 gene in genotype AB in comparison to genotype AA. There was the same CTT deletion mutation of BMP15 gene in both Small Tail Han sheep and Dorset sheep as that in Belclare, Cambridge, Hanna and Inverdale ewes. The Small Tail Han ewes with mutation heterozygous genotype AB had 0.20 (P >0.05) lambs more than that those with wild type AA. These results preliminarily indicate the CTT deletion mutation of BMP15 gene has no significant effect on prolificacy of Small Tail Han sheep.