绵羊催乳素受体基因外显子10的多态性分析

Polymorphism Analysis for Exon 10 of Prolactin Receptor Gene in Sheep

将催乳素受体(prolactin receptor,PRLR)基因作为绵羊高繁殖力的候选基因,对其外显子10设计2对引物,采用PCR-SSCP技术检测其在常年发情的湖羊及季节性发情的中国美利奴羊、罗米丽羊和罗米丽×中国美利奴(新疆军垦型)中的单核苷酸多态性。结果表明,引物P1、P2的扩增片段均有多态性。与已知序列相比,P1扩增片段的AB型在第53 bp处出现A→G突变、在81 bp处出现G→A突变,BB型在该片段第53 bp处发生A→G的突变;对于P2扩增片段,CC、DD、CE和EF型均在第89 bp处发生C→T的突变,导致氨基酸由脯氨酸变为亮氨酸(Pro→Leu),DD型还在146 bp处出现了C→G的突变,此突变导致氨基酸由丙氨酸变为甘氨酸(Ala→Gly);CE型在该片段第132 bp处发生G→A的突变,未导致氨基酸的改变;EF型还在第132 bp处和第167 bp处分别发生了G→A、C→T突变,第167 bp处的突变导致氨基酸由脯氨酸变为亮氨酸(Pro→Leu)。通过卡方独立性检验结果发现,4种绵羊在P1、P2引物扩增片段上各基因型的构成与品种间有极显著差异(P<0.01),说明PRLR基因对绵羊的繁殖性状有一定的影响。

Prolactin receptor （PRLR） gene was studied as a candidate gene for the prolificacy in sheep. Two pairs of primers were designed to detect single nucleotide polymorphisms of exon 10 of PRLR gene in both nonseasonal estrous breed（Hu sheep） and seasonal estrous breed（China Merino, Romilly Hills and Romilly Hills × China Merino） by PCR-SSCP. The result showed that the products amplified by primer P1, P2 displayed polymorphisms. For primer P1, sequencing revealed two mutations （53A→G and 81G→A） of PRLR gene in the genotype AB and only one mutation （53A→G） was found in the genotype BB in comparison with reported sequence. And these mutations did not cause any amino acid change. For primer P2, sequencing revealed one mutation（89C→T） in genotype CC,DD,CE,EF and this mutation resulted in an amino acid change of Pro→Leu. Another mutation （146C→G） of PRLR gene in the genotype DD and this mutation resulted in an amino acid change of Ala→ Gly. One mutation （132G→A） was detected in the genotype EF and CE,this mutation resulted in no amino acid change. One mutation （167G→A） was also detected in the genotype EF and led to an amino acid change Pro→Leu. The result of x^2 independence test indicated that the distribution and constitution of genotypes at P1 and P2 of the exon 10 of PRLR gene showed significant differences among 4 sheep breeds（P〈0.01）.