The Levels of genetic differentiation of small tailed han sheep and tan sheep populations using structural loci

صينى. 采用中心产区典型群随机抽样方法和多种电泳技术检测60只小尾寒羊、73只滩羊编码血液蛋白17个结构基因座上的变异，引用国内外14个绵羊群体相同资料进行比较分析，探讨其遗传分化水平。研究表明：(1) 小尾寒羊、滩羊结构基因座平均杂合度分别为0.2360和0.2587；平均多态信息含量分别为0.1974、0.2102；平均有效等位基因数分别为1.5723和1.5751。(2) 4个组合（分别为4个、6个、13个及16个绵羊群体）的基因分化系数分别为0.049323、0.059987、0.1728和0.201256，说明湖羊、同羊、小尾寒羊和滩羊4个绵羊群体结构基因座的基因分化程度低；这4种绵羊与蒙古国绵羊的基因分化程度次之；蒙古羊系绵羊和南亚羊及欧洲羊之间基因传分化程度较高。(3) 前人关于小尾寒羊、滩羊由蒙古羊分化而来的考证得到遗传学实验的进一步证明，湖羊、同羊、小尾寒羊和滩羊受蒙古羊血统的影响递减。群体间亲缘关系远近与其所处地理位置远近并未表现出紧密相关。

إنجليزي. Using the method of “ random sampling in typical colonies of the central area of the habitat ” and several electrophoresis techniques, the variations of 17 structural loci encoding blood proteins in 60 Small Tailed Han sheep and 73 Tan sheep were examined and compared with those of 14 other sheep populations in China and other countries to explore their levels of genetic differentiation. The average heterozygosity of Small Tailed Han sheep and Tan sheep was 0.2360 and 0.2587, respectively. The average polymorphic information content valued 0.1974 and 0.2102, respectively. The average effective numbers of alleles were 1.5723 and 1.5751, respectively. The coefficients of gene differentiation in four groups (including 4, 6, 13, 16 sheep populations, respectively) were 0.049323, 0.059987, 0.1728 and 0.201256, respectively, indicating that the degree of gene differentiation at structural loci in Hu sheep, Tong sheep, Small Tailed Han sheep and Tan sheep was least, that in above-mentioned four sheep populations and two Mongolian sheep populations was the second, and that in sheep populations belonging to Mongolian sheep group, South Asian sheep and European sheep was the highest. The earlier researchers’ conclusions that Small Tailed Han sheep and Tan sheep both evolved from Mongolian sheep was further verified by the results in this study. Hu sheep, Tong sheep, Small Tailed Han sheep and Tan sheep were decreasingly affected by the bloodline of Mongolian sheep. The relationships among sheep populations were not closely related to the distances among sheep populations.