绵羊PDGF-D基因多态性与尾型的关联

Association of the PDGF-D Gene Genetic Variation with Sheep Tail Traits

旨在研究血小板源性生长因子-D(platelet-derived growth factor-D, PDGF-D)与绵羊尾型的关系,寻找可用的分子标记,同时对前期的研究结果进行验证。本研究在533只绵羊(湖羊、藏羊、杜泊×湖羊杂交羊)试验群体中,选取藏羊、湖羊两个品种各30个个体的血液样本,等量混合分别构建两个DNA混池,对PDGF-D基因的外显子及其上下游1 000 bp扩增,目的片段测序分析后,采用飞行质谱方法对检测到的SNP位点进行基因分型,Haploview4.1软件对突变位点进行连锁不平衡分析,使用SPSS19.0软件对PDGF-D基因SNP位点与尾型性状进行关联分析。结果显示,在PDGF-D基因及其上下游1 000 bp共找到6个突变位点,其中rs5、rs27、rs28与尾长、尾宽及尾周长均相关,rs6、rs19仅与尾长相关,rs13与尾宽、尾周长均显著相关(P<0.05)。连锁不平衡分析结果表明,rs6～rs13之间存在强连锁;组合基因型与尾型关联分析结果显示,CCGG型个体无论是在尾长、尾宽还是在尾周长上,其平均值均显著(P<0.05)或者极显著(P<0.01)低于其他组合基因型,但在群体中的数量较少。结果表明,PDGF-D基因对绵羊的尾型有着较为显著的影响,其SNP位点作为分子标记对于绵羊尾型选育工作有着一定的指导意义,可考虑将CCGG型作为筛选小尾绵羊的潜在分子标记,但是该基因型个体在群体中所占的比重较小,可适当增强人工选育以扩大数目。

We studied the possibility of the PDGF-D gene to be a novel candidate gene affecting the sheep tail traits,in order to verify the previous results,as well as to find new molecular markers related to the sheep tail traits.In the 533 sheep experiment group(Hu sheep,Tibetan sheep,Dorper sheep×Hu sheep),30 DNA samples with a fixed concentration from Hu sheep and Tibetan sheep respectively were selected to construct the DNA pool,primers were designed to amplify exons and 1 000 bp of upstream and downstream regulatory regions.PCR products were tested and the target segments were sequenced.Sequenom Mass-array technology was used to genotype the detected SNPs.Haploview 4.1 was used to construct haplotypes and analyze linkage disequilibrium of the polymorphic loci.Association analysis between the SNPs of PDGF-D gene and the tail traits was performed using SPSS 19.0 software.The results showed that 6 SNPs were detected.rs5,rs27 and rs28 were significantly related to tail length,tail width and tail perimeter(P<0.05).rs6 and rs19 were only significantly involved in tail length(P<0.05).rs13 was significantly related to tail width and tail perimeter(P<0.05).The result of linkage disequilibrium analysis showed that there was close linkage from rs6 to rs13.Meanwhile,the association analysis of combined genotypes of rs6-rs13 with tail traits revealed that individuals with CCGG combined genotype were significantly lower than the individuals with other combined genotypes in tail length,tail width and tail perimeter(P<0.05 or P<0.01),but the number of individuals with CCGG was less in population.The results indicate that PDGF-D gene has significant effect on sheep tail traits,and the SNPs of PDGF-D gene are potentially valuable as genetic markers for breeding.The CCGG genotype can be considered as the potential molecular marker to breed small-tailed sheep.The amount of individuals with CCGG combined genotype should be expanded further.