贵州黄牛mtDNA D-loop 遗传多样性研究

对贵州4个地方黄牛品种共计82个个体的线粒体DNA D-loop区全序列910 bp进行分析，检测到31种单倍型，其核苷酸多态位点65个，约占所测核苷酸总长的7.14%，其中有62个转换，2个颠换，1个转换/颠换共存。贵州4个黄牛品种mtDNA D-loop区核苷酸多样度（π值）为2.16%～2.61%，单倍型多样度（H）为0.695～0.909，表明贵州黄牛mtDNA遗传多样性比较丰富。根据单倍型构建了贵州4个黄牛品种的NJ分子系统树。聚类表明,贵州黄牛有普通牛和瘤牛2大母系起源，其影响较为均一。并探讨了用核苷酸多样度π值的大小来衡量黄牛群体遗传分化程度的可行性。

Genetic Diversity of Mitochondrial DNA D-loop Sequences in Cattle Breeds in Guizhou

The complete mitochondrial D-loop sequences, 910 bp in length, in 82 individual cattle from 4 breeds in Guizhou province were analyzed. The results revealed 31 mitochondrial haplotypes, 65 polymorphic sites, covering 7.14% of the entire length of the sequence. Among these polymorphic sites, there were 62 transitions, 2 transversions and 1 coexistent site of transition and transversion. The nucleotide diversity (pi value) and haplotype diversity (H) estimated from mtDNA D-loop region in 4 cattle breeds in Guizhou varied from 2.16%-2.61% and 0.695-0.909, respectively, showing that abundant mitochondrial genetic diversity exists in Guizhou cattle breeds. The Neighbor-Joining molecular phylogenetic tree of mtDNA D-loop of 4 Guizhou cattle breeds was constructed according to the 31 haplotypes. The NJ tree indicated that the origin of cattle breeds was from Bos taurus and Bos indicus which had nearly the same influence on cattle breeds in Guizhou. The feasibility of applying nucleotide diversity (pi value) to the evaluation of bovine genetic differentiation was discussed.