西藏牛亚科部分群体线粒体DNA遗传多样性研究

Genetic diversity of mitochondrial DNA of some subfamilies of cattle in Tibet

为了在从母系遗传上研究西藏牛亚科部分群体的遗传多样性和亲缘进化关系,通过PCR扩增西藏巴美牛、当地土种牛、驼峰牛以及引进娟珊牛4个群体18个个体的mtDNA D-loop控制区全序列,并测序.结果显示,D-loop区大小分布在892 bp～912 bp之间,不同群体间存在长度差异,同时西藏各群体牛D-loop区富含A、T碱基,共检测到颠换、转换、插入、缺失以及颠换和转换共存同一位点等5种突变类型.4个群体发现17种单倍型,多态位点达到125个,平均单倍型多样性约为0.992,平均核苷酸多样性约为0.039,表明西藏黄牛群体遗传多样性丰富.系统进化分析显示17种单倍型大致可以分为三大类,在其进化过程中出现相互交流的情况,巴美牛和驼峰牛亲缘关系最近,当地土种牛仍为较纯的黄牛,西藏黄牛群体不包含瘤牛单倍型,均为普通牛单倍型.

To investigate the genetic diversity, clustering relationship and phylogenetic evolution of mtDNA D-loop region of some subfamilies of cattle in Tibet, the mtDNA D-loop sequence was amplified and sequenced in 18 bovine individuals from 4 populations(BM, TZ, TF, JS). Results showed that the length of the mtDNA D-loop was from 892 bp to 912 bp, different populations had length difference and were rich in A and T bases, and that five types of mutations such as transversion, transition, insertion, deletion, transition and transversion coexistence were detected. Seventeen haplotypes were found in the 4 populations, and the number of polymorphic loci reached 125. The average haploid type diversity and nucleotide diversity were 0.992 and 0.039 respectively, indicating a high level of genetic diversity in Tibetan cattle populations. Phylogenetic evolution analysis showed that 17 haplotypes could be divided into three categories. Tibetan cattle breeds do not contain Bos indicus haplotypes, all of which are Bos taurus haplotypes, different populations interacting in the process of evolution. The crossbreed cattle and TF cattle have the highest homology, local native cattle can be used as a true bred population for utilization.