新疆13个绵羊群体遗传多样性及遗传分化的研究

Stndy on Genetic Diversity and Genetic Differentiation of 13 Sheep Populations in Xinjiang Uygur Autonomous Region

利用10个微卫星标记对新疆13个绵羊群体的遗传多样性和遗传分化进行了分析。通过计算多态信息含量（PIC）、平均杂合度（H）、群体内近交系数（Fis）、遗传分化系数（Fst）、总群体近交系数（Fit）和基因流（Nm）等参数,评估各品种遗传多样性和品种间遗传分化。结果表明：13个绵羊群体10个微卫星标记的平均多态信息含量为0.6803;平均杂合度为0.7192,其中中国美利奴羊平均杂合度最高为0.7530,山区和田羊最低为0.6754;13个绵羊群体总近交系数为0.1066,群体内近交系数为0.0565,群体间基因分化系数为0.0531,说明5.65%的遗传变异来自群体间,94.35%的遗传变异来自群体内个体间的差异;基因流Nm平均值为4.4621（3.0808~7.4589）,说明各种群间存在或者在过去某个时期发生基因交流;各种群间平均遗传距离较低,为0.1702,平均遗传一致度数值较高,为0.8448,也再次证明了新疆13个绵羊群体间分化程度不高。基于Nei′s标准遗传距离运用UPGMA聚类法获得的新疆13个绵羊群体的聚类图与其品种育成史和地理分布基本相一致。

The genetic diversity and genetic differentiation of 13 sheep populations in Xinjiang Uygur Autonomous Region of China were surveyed using 10 microsatellite markers.Using polymorphism information content（PIC）,average heterozygosity（H）,the heterozygote deficit within population（Fis）,the global heterozygote deficit across of all populations（Fit）,the coefficients of genetic differentiation（Fst） and gene flow（Nm）,we evaluated the genetic diversity and genetic differentiation.The results showed that the mean polymorphism information content was 0.6803.the mean heterozygosity was 0.7192,the lowest was that of Chinese Merino sheep（0.7530）,the highest was that of Hetian mountain sheep（0.6754）.the global heterozygote deficit across of all populations amounted to 0.1066,the heterozygote deficit within population amounted to 0.0565,the heterozygote deficit within 13 sheep populations was 0.0565,which indicated that 5.65% of the total genetic variation came from breed differences,and the remaining 94.355 came from differences among individuals in each population.the mean gene flow was 4.4621,ranging from 3.0808 to 7.4589,and indicated that gene flow between populations occurred some time in the past.the lower mean genetic distance（0.1702） and high genetic identity（0.8448） between populations proved once again that the 13 sheep populations in Xinjiang Uygur Autonomous Region were lowly differentiated with all the loci.The dendrogram constructed from Nei＇s genetic distances and UPGMA method correctly indicated the phylogenetic relationships and geographical distribution among the 13 sheep populations.