催乳素基因多态性及其与小尾寒羊高繁殖力关系的研究

设计5对引物，采用PCR-SSCP技术检测催乳素（prolactin，PRL）基因外显子1至外显子5在高繁殖力绵羊品种（小尾寒羊和湖羊）和低繁殖力绵羊品种（多赛特、特克塞尔和考力代）中的单核苷酸多态性，同时研究该基因对小尾寒羊高繁殖力的影响。通过克隆测序首次获得了绵羊PRL基因外显子全序列。结果表明：外显子2在5个绵羊品种中均存在单核苷酸多态性，而其它4个外显子只在湖羊中存在单核苷酸多态性。本研究初步表明小尾寒羊PRL基因外显子2的CC型平均产羔数分别比CD型和DD型多0.39只（P<0.05）和0.98只（P<0.05），CD型和DD型小尾寒羊平均产羔数差异不显著（P>0.05）。

Polymorphism of Prolactin Gene and Its Relationship with Prolificacy of Small Tail Han Sheep

The prolactin (PRL) gene was studied as a candidate gene for the prolificacy of Small Tail Han sheep. Single nucleotide polymorphisms (SNPs) of exon 1 to exon 5 of PRL gene were detected in high fecundity breeds (Small Tail Han and Hu sheep) and low fecundity breeds (Dorset, Texel and Corriedale sheep) with five pairs of primers by PCR-SSCP. The entire exon sequence of ovine PRL gene was obtained firstly by means of cloning and sequencing. SNPs of the exon 2 were detected in five sheep breeds and the other exons (exon 1, exon 3 to exon 5) only in Hu sheep. For the exon 2 of PRL gene, the Small Tail Han ewes with genotype CC had 0.39 (P <0.05) or 0.98 (P <0.05) lambs more than those with genotype CD or DD; the Small Tail Han ewes with genotype CD had 0.59 (P >0.05) lambs more than those with genotype DD.