三种绵羊BMP15基因第二外显子多态性及与产羔数的相关性分析

绵羊存在影响多胎性状的不同主效基因,选择影响Romney Hanna绵羊和Cambridge绵羊高繁殖力的骨形态发生蛋白15 (bone morphogenetic protein 15, BMP15)为候选基因,采用PCR-SSCP的方法检测BMP15基因外显子Ⅱ第747位点(T747→C)和755位点(T755→C)在蒙古羊、甘肃高山细毛羊、小尾寒羊三种绵羊母羊中的多态性,同时还研究了上述两处突变对三种绵羊产羔数的影响。表明:(1)一共检测到野生纯合型AA、突变杂合型AB (T747→C)、AC (T755→C)三种不同的基因型,AA为优势基因型,A为优势等位基因;(2)三种基因型在甘肃高山细毛羊中均被检测到,而蒙古羊和小尾寒羊中未检测出AB基因型;(3)突变杂合型蒙古羊(AC)比野生纯合型(AA)的平均产羔数多0.27只(p<0.05)。(4)AC的基因型频率,双羔母羊和多羔母羊均高于单羔母羊。根据以上实验推测,BMP15第755位点发生的T→C突变(AC型)对蒙古羊一胎产双羔影响十分显著,甘肃高山细毛羊中AC基因型的绵羊其产羔数有比AA基因型和AB基因型多的趋势,因此该位点可能是一个影响绵羊高繁殖力潜在的DNA标记。

Three Breeds of Sheep BMP15 Gene Exon 2 Polymorphism and Its Correlation with Litter Size

There are different major genes affecting prolific trait in sheep. We took bone morphogenetic protein15(BMP-15) as candidate gene, which influenced Romney Hanna sheep and Cambridge sheep with high fecundity.We used PCR-SSCP to detect polymorphisms of BMP15 exon two, locus 747th(T747→C) and 755th(T755→C)in Mongolia sheep, Gansu Alpine Merino sheep and Small Tailed Han sheep, and also studied the effect of two mutations on three kinds of sheep lambing number. The results showed that:(1) There were three types of genotypes including wild homozygous AA, mutant heterozygous AB(T747→C) and AC(T755→C). AA was the dominant genotype, and A was the dominant allele;(2) These three genotypes were detected in the Gansu Alpine Merino sheep,but the AB genotype was not detected in Mongolia sheep and Small Tail Han sheep;(3) The Mongolia sheep with mutant heterozygous AB had 0.27 lambs more than those with wild homozygous type AA(p<0.05).(4) The genotype frequency of AC in double lambing ewes and multiparous ewes were higher than that of single lambing ewes.According to the above experimental results, we suggested that the T→C mutation(AC) at BMP15 755 th site had a significant effect on twin lambs of Mongolia sheep. We also found a tendency that the litter size of sheep which had AC genotype was more than that of AA and AB genotypes in Gansu Alpine Merino sheep, and this locus may be a potential DNA marker for affecting high prolificacy of sheep.