西藏牦牛SRAP遗传多样性及分类进化研究

用4对SRAP分子标记引物对西藏11个牦牛类群和四川麦洼牦牛的DNA进行扩增,研究其遗传多样性和分类关系。结果表明,在335头牦牛中,共得到29个基因位点,其中有19个多态位点,多态率占65.52%。12个牦牛群体间的Nei’s遗传多样性和Shannon多样性指数分别为0.048 2和0.073 4,遗传相似系数在0.781 1-0.989 1。巴青牦牛和康布牦牛的遗传多样性指数较其他类群高,分别为0.095 5和0.090 0;桑日牦牛类群的遗传多样性指数最低,仅为0.008 5。这些结果表明,12个牦牛类群的SRAP遗传多样性较低。根据Nei’s遗传距离,利用UPGMAM构建聚类关系图结果显示,嘉黎牦牛、帕里牦牛、类乌齐牦牛、桑桑牦牛、康布牦牛、巴青牦牛、丁青牦牛、斯布牦牛和麦洼牦牛聚为一大类,然后依次才与桑日牦牛、工布江达牦牛和江达牦牛相聚在一起,显示在SRAP分子遗传标记所反映的牦牛基因组的遗传结构中,江达牦牛、工布江达牦牛和桑日牦牛与其他牦牛群体间的亲缘关系较远,牦牛的这种亲缘关系与其地理分布也不一致,说明这12个牦牛的起源、演化关系较复杂,有待于进一步研究分析。

Analysis of Genetic Diversity and Classification of Tibetan Yak Breeds by SRAP Molecular Markers

To analyze the genetic diversity and phylogeny relationship,we used 4 pairs SRAP markers among 11 Tibetan yak populations and Sichuan Maiwa yak.The results showed that the numbers of polymorphic loci were 19 and the percentage of polymorphic loci is 65.52 in all.The indexes of Nei’s gene diversity and the Shannon’s information were 0.048 2,0.073 4 respectively.The Genetic similarity coefficient is from 0.781 1 to 0.989 1.Genetic diversity showed that the highest populations were Baqing yak(0.095 5) and Kangbu yak(0.090 0),and the lowest one was Sangri yak(0.008 5).All data indicated the genetic diversity of SRAP was low in 12 yaks’ populations.Based on the Nei’s genetic distance,cluster diagram with UPGMAM,the tree showed Jiali yak,Pali yak,Leiwuqi yak,Sangsang yak,Kangbu yak,Baqing yak,Dingqing yak,Sibu yak and Maiwa yak clustered into one category,and then followed it with Sangri yak,Gongbujiangda yak and Jiangda yak.The result show the Sangri yak,Gongbujiangda yak and Jiangda yak’s genome genetic structure different from others by used SRAP genetic markers.The genetic relationship is unrelated with geographic distribution.Above all revealed that the origin and evolution of 12 yaks populations were complicated,and to be further research.