小尾寒羊高繁殖力候选基因BMP15和GDF9的研究

Study on BMP15 and GDF 9 as Candidate Genes for Prolificacy of Small Tail Han Sheep

以控制Belclare和Cambridge绵羊高繁殖力的骨形态发生蛋白 15 (bonemorphogeneticprotein 15 ,BMP15 )基因和生长分化因子 9(growthdifferentiationfactor 9,GDF9)基因为候选基因 ,采用PCR RFLP技术检测BMP15基因和GDF9基因在高繁殖力绵羊品种 (小尾寒羊、湖羊 )以及低繁殖力绵羊品种 (多赛特羊、特克塞尔羊、德国肉用美利奴羊 )中的单核苷酸多态性 ,同时研究这两个基因对小尾寒羊高繁殖力的影响。结果表明 :在 5个绵羊品种中都没有检测到GDF9基因的G8突变 (C→T) ,也没有检测到BMP15基因的B4突变 (G→T)。高繁殖力的小尾寒羊在BMP15基因编码序列第 718位碱基处发生了与Belclare绵羊和Cambridge绵羊相同的B2突变 (C→T) ,而其余 4个绵羊品种则没有发生这种突变。对于BMP15基因的B2突变 ,在小尾寒羊中检测到AA、AB两种基因型 ,A等位基因频率为 0 734,B等位基因频率为 0 2 6 6。小尾寒羊与其余 4个绵羊品种间B2突变基因型分布差异极显著 (P <0 0 0 1)。突变杂合基因型 (AB)小尾寒羊平均产羔数比野生纯合基因型 (AA)多 0 6 2只 (P <0 0 1)。研究结果表明 ,BMP15B2突变对小尾寒羊高繁殖力影响作用十分明显 。

Bone morphogenetic protein 15 (BMP15) gene and growth differentiation factor 9 (GDF9) gene which control the fecundity of Belclare and Cambridge ewes were studied as candidate genes on the prolificacy of Small Tail Han sheep.Single nucleotide polymorphism of GDF 9 gene and BMP15 gene was detected in both high fecundity sheep breeds (Small Tail Han sheep and Hu sheep) and low fecundity sheep breeds (Dorset sheep,Texel sheep and German Mutton Merino sheep) by PCR-RFLP.The results showed that the G8 mutation (C→T) of GDF 9 gene and the B4 mutation (G→T) of BMP15 gene were not detected in five sheep breeds.There was the same B2 mutation (C→T) of BMP15 gene in Small Tail Han sheep as that in Belclare and Cambridge ewes.The same B2 mutation did not exist in other four sheep breeds.Concerning the B2 mutation of BMP15 gene,AA and AB genotypes were detected in Small Tail Han sheep,frequency of A allele was 0.734,frequency of B allele was 0.266.The BMP15 B2 genotype distributions were high significantly different (P<0.001) between Small Tail Han sheep and other four sheep breeds.The ewes with heterozygous mutant AB had 0.62 (P<0.01) lambs more than those with wild homozygous type AA in Small Tail Han sheep.These results indicated that the B2 mutation of BMP15 gene had significant effect on the fecundity of Small Tail Han sheep and ruled out the possibility that the fecundity of Small Tail Han sheep was affected by the G8 mutation of GDF 9 gene and the B4 mutation of BMP15 gene.