绵羊PRLR和CARTPT基因多态性与产羔数的关联分析

试验旨在研究绵羊催乳素受体(Prolactin receptor,PRLR)基因g.38976954C>A位点多态性和可卡因-苯丙胺调控转录肽(CART prepropeptide,CARTPT)基因g.9856267C>A、g.9854141G>C位点多态性与绵羊产羔数之间的关系,为绵羊多羔新品系的选育和高繁殖力机理研究提供参考。采用重测序和Sequenom MassARRAY?誖SNP技术对常年发情(小尾寒羊、湖羊、策勒黑羊)和季节性发情(草原型藏羊、苏尼特羊、滩羊、萨福克羊)的不同绵羊品种PRLR、CARTPT基因进行检测分型,然后与小尾寒羊产羔数关联分析。结果表明:g.38976954C>A位点有CC、CA和AA三种基因型,该位点基因型频率和等位基因频率在常年发情、季节性发情绵羊品种间差异不显著(P>0.05);g.9856267C>A位点存在CC、CA和AA三种基因型,g.9854141G>C位点存在GG、GC和CC三种基因型,这2个位点的基因型频率和等位基因频率在常年发情、季节性发情绵羊品种间差异均极显著(P<0.01)。群体遗传学分析结果表明,g.38976954C>A位点在小尾寒羊、草原型藏羊、滩羊和策勒黑羊中均表现为低度多态(PIC<0.25),在苏尼特羊、湖羊和萨福克羊中均表现为中度多态(0.25A位点在7个绵羊品种中均表现为低度多态(PIC<0.25);g.9854141G>C位点在小尾寒羊、苏尼特羊、草原型藏羊、滩羊、湖羊和策勒黑羊中均表现为低度多态(PIC<0.25),在萨福克羊中表现为中度多态(0.25A位点在7个绵羊品种中均处于哈代-温伯格不平衡状态(P<0.05);g.9856267C>A位点在草原型藏羊和湖羊中处于哈代-温伯格不平衡状态(P<0.05);g.9854141G>C位点在7个绵羊品种中均处于哈代-温伯格平衡状态(P>0.05)。关联分析表明,PRLR基因g.38976954C>A位点不同基因型与小尾寒羊各胎产羔数之间无显著关联(P>0.05),该位点不适用于小尾寒羊多羔性状选育;CARTPT基因g.9856267C>A和g.9854141G>C位点不同基因型与小尾寒羊各胎产羔数之间无显著关联(P>0.05),但这2个位点不同基因型各胎产羔数相差较大,推测该位点可能对产羔有影响。

Polymorphisms of Sheep PRLR and CARTPT Genes and Their Association with Litter Size

To explore the association between PRLR,CARTPT gene polymorphism and litter size in sheep,providing references for the breeding of new strains of sheep with high prolificacy and research on high reproductive mechanism of sheep.Year-round estrous sheep breeds(Small Tail Han sheep,Cele Black sheep and Hu sheep)and seasonal estrous sheep breeds(Tan sheep,Sunite sheep,Suffolk sheep and Prairie Tibetan sheep)were selected and Sequenom MassA RRAYSNP assay was applied to genotype g.38976954C>A locus of PRLR gene,g.9856267C>A and g.9854141G>C loci of CARTPT gene.Then the association was analyzed between PRLR,CARTPT gene and litter size in Small Tail Han sheep.The result of genotyping showed that three genotypes were found at g.38976954C>A,g.9856267C>A and g.9854141G>C loci in both year-round estrous and seasonal estrous sheep,genotype frequency and allele frequency were not significantly different between year-round estrous and seasonal estrous sheep(P>0.05)in g.38976954C>A locus of PRLR gene,and were high significantly different between year-round estrous and seasonal estrous sheep(P<0.01)in g.9856267C>A and g.9854141G>C loci of CARTPT gene.Population genetic analysis showed that the g.38976954C>A locus was at low polymorphism(PIC<0.25)in Small Tail Han sheep,Prairie Tibetan sheep,Tan sheep and Cele Black sheep,and at moderate polymorphism(0.25A locus was at low polymorphism(PIC<0.25)in all sheep breeds,the g.9854141G>C locus was at low polymorphism(PIC<0.25)in Small Tail Han sheep,Sunite sheep,Prairie Tibetan sheep,Tansheep,Hu sheep and Cele Black sheep,and at moderate polymorphism(0.25A locus of all sheep breeds was not under Hardy-Weinberg equilibrium(P<0.05),the g.9856267C>A locus of Prairie Tibetan sheep and Hu sheep was not under Hardy-Weinberg equilibrium(P<0.05),the g.9854141G>C locus of all sheep breeds was under Hardy-Weinberg equilibrium(P>0.05).Association analysis indicated that the polymorphism of g.38976954C>A had no correlation with the litter size of Small Tail Han sheep(P>0.05),g.38976954C>A might not be suitable for breeding of Small Tail Han sheep,that the polymorphism of g.9856267C>A and g.9854141G>C had no correlation with the litter size of Small Tail Han sheep(P>0.05),but the two SNPs of CARTPT gene had big difference in litter size of Small Tail Han sheep,supposing that polymorphism of g.9856267C>A and g.9854141G>C might have effect on litter size.