为了解西藏牦牛品种或类群的遗传多样性和亲缘关系, 文章选用8对微卫星标记引物, 利用PCR和复合电泳银染技术, 通过计算基因频率(P)、有效等位基因数(Ne)、群体杂合度(He)、多态信息含量(PIC)和遗传距离(D), 对西藏11个牦牛类群共480个个体进行了遗传多样性和系统进化分析。结果表明：(1) 8个微卫星标记在西藏牦牛类群中均表现出多态性, 且均属高度多态位点, 遗传多样性丰富; (2) 8个微卫星标记的平均多态信息含量在西藏牦牛类群中均高于0.5, 其中HEL13最高为0.8496, TGLA57最低为0.7349; 在11个牦牛类群中, 桑日牦牛的平均多态信息含量最高(0.7949), 该群体内部存在较多的遗传变异; 丁青牦牛最低(0.7505), 则群体相对较纯; (3) 在11个牦牛类群中, 其杂合度大小分别为：桑日(0.8193)>江达(0.8190)>桑桑(0.8157)>巴青(0.8150)> 康布(0.8123)>嘉黎(0.8087)>工布江达(0.8054)>斯布(0.8041)>类乌齐(0.8033)>帕里(0.8031)>丁青(0.7831), 西藏东部牦牛的遗传多样性较西部的遗传多样性大, 预示西藏东部可能是牦牛的发源地之一; (4) 根据遗传距离, 用UPGMA法构建聚类关系, 表明西藏11个牦牛类群可以分为三大类, 即嘉黎牦牛、帕里牦牛、桑桑牦牛、巴青牦牛、类乌齐牦牛、康布牦牛聚为一类, 斯布牦牛、工布江达牦牛、桑日额牛、江达牦牛聚为一类, 丁青牦牛单独成为一类。综上所述, 西藏牦牛的遗传多样性较丰富, 所选微卫星标记可用于西藏牦牛遗传多样性的评估。
To assess the genetic diversity and relationship of the Tibetan yak breeds. The genetic diversity and phylogenies of a total of 480 individual from 11 Tibetan yak groups were analyzed using PCR and multiplex gel electrophoresis of silver staining technology with eight pairs of microsatellite markers.The result showed that these markers were highly polymorphic loci with rich genetic diversity in the Tibetan yak populations.The average polymorphic information content (PIC) in 11 groups of yak were higher than 0.5. The highest HEL13 was 0.8496, and the lowest TGLA57 was 0.7349. Among them, the PIC of Dingqing yak was minimum (0.7505), indicating that the group is relatively pure.Sangri Yak had the highest PIC value (0.7949) indicating greater genetic variationwithinthe groups. Among the 11 groups examined, the order of heterozygosity size wasSan-gri(0.8193)>Jiangda(0.8190)>Sangsang(0.8157)>Baqing(0.8150)>Kangbu(0.8123)>Jiali(0.8087)>Gongbujiangda(0.8054)>Sibu(0.8041)>Leiwuqi(0.8033)>Pali(0.8031)>Dingqing(0.7831). The groups from eastern Tibet had grater genetic diversity than those from Western Tibet, which indicate that Tibet may be one of the cradles of the yak.According to the genetic distance, the cluster relationship constructed with UPGMA and NJ methods showed that 11 yak groups in Tibet could be divided into three forms. In summary,Tibet yak has abundant genetic diversity and the selected microsatellite markers can be used to evaluategenetic diversity of Tibetan yak.
