绵羊微卫星471U和FecB基因多态性及连锁分析

Polymorphic and linkage analysis of microsatellite 471U and FecB gene in sheep

以高繁殖力(小尾寒羊和湖羊)及低繁殖力(特克塞尔和道塞特)4个绵羊品种为研究对象,分析与绵羊高繁殖力主效基因FecB紧密连锁的微卫星基因座471U在高繁殖力和低繁殖力绵羊品种中多态性,探讨该微卫星基因座与小尾寒羊FecB基因的连锁不平衡关系。结果表明:高繁殖力品种小尾寒羊和湖羊在骨形态发生蛋白受体IB(BMPRIB)基因编码序列第746位碱基处发生了FecB突变(A746G),而在低繁殖力的特克塞尔和道塞特绵羊中未检测到该突变;小尾寒羊BB、B+、的基因型频率分别为0.494、0.392和0.114,湖羊BB、B+的基因型频率分别为0.815和0.185。471U基因座在4个绵羊品种的466只个体中共检测到3个等位基因和5种基因型;小尾寒羊(316只)、湖羊(54只)、特克塞尔(48只)、道塞特(48只)和BB型(156只)、B+型(124只)、型(36只)小尾寒羊以及BB型(44只)、B+型(10只)湖羊群体中优势等位基因大小分别为200、204、200、200、200、200、200、204、204bp,其频率分别为0.767、0.926、1.000、0.625、0.808、0.730、0.722、0.943、0.850。连锁不平衡分析显示,小尾寒羊FecB基因B等位基因与471U基因座200bp等位基因以及+等位基因与471U基因座204bp等位基因均存在一定的连锁不平衡(D′分别为0.430、0.444)。

Polymorphisms of microsatellite locus 471U, which was closely linked to the ovine fecundity gene FecB, were detected in prolific （Small Tailed Han and Hu sheep） and non prolific breeds of sheep （Texel and Dorset）. The link age disequilibrium between 471U locus and FecB gene in Small Tailed Han was also analyzed. There was the same FecB mutation （A746G） of BMPR-1B gene in both prolific breeds as that in Booroola Merinos. FecB mutation was absent in Texel and Dorset. The genotype frequencies of BB, B＋ and ＋＋ were 0. 494, 0. 392 and 0. 114 for Small Tailed Han re spectively, and those of BB and B＋ were 0. 815 and 0. 185 for Hu. There were three alleles and five genotypes detected at 471U locus in 466 individuals totally including four sheep breeds. The preponderant allele was 200, 204, 200, 200, 200, 200, 200, 204, 204 bp with the frequency of 0. 767, 0. 926, 1. 000, 0. 625, 0. 808, 0. 730, 0. 722, 0. 943, 0. 850 in Small Tailed Han （n=316）, Hu （n=54）, Texel （n=48）, Dorset （n 48）, BB group （n=156）, B＋ group （n=124） and ＋＋ group （n=36） from Small Tailed Han, and BB group （n=44） and B＋ group （n=10） from Hu sheep, respec tively. In Small Tailed Hart, linkage analysis indicated that there was certain linkage disequilibrium between 200 bp allele of 471U locus and B allele of FecB gene （D＇=0. 430）, and certain linkage disequilibrium between 204 bp allele of 471U locus and ＋allele of FecB gene （D＇=0. 444）.