基于D-loop区部分序列分析黔、陕、湘3个大鲵种群系统发育关系和遗传分化

Phylogenetic Relationship and Genetic Differentiation Analysis of Giant Salamander of Three Populations in Qian,Shaan and Xiang based on Partial Sequence in D-loop Region

为弄清贵州大鲵群体与中国其他大鲵群体的遗传关系,探究贵州大鲵种群遗传背景,本研究测定了贵州、陕西、湖南共82条大鲵的mt DNA D-loop区部分序列,进行系统发育关系和遗传分化的分析。结果显示:82条序列中共检出7种单倍型序列,贵州大鲵群体有6个单倍型、陕西群体3个单倍型、湖南群体只有1个单倍型。综合动物遗传多样性指数,得出遗传多样性水平依次排序为贵州>陕西>湖南,但均处于低水平遗传多样性的状态。由于地理隔离的原因,种群间基因流Nm<1,遗传分化显著,但没有达到种群分化的水平。贵州种群与湖南种群在14~35万年前发生分歧,与陕西种群在12~30万年前发生遗传分歧;陕西与湖南种群发生分歧的时间则短得多,约在2~5万年前。贵州大鲵种群中可能出现隐种。

In order to find out genetic relationship between giant salamander in Guizhou and other regions in China, as well as to study the genetic background of Guizhou giant salamander, partial sequences in D-loop region of 82 samples were detected to accomplish the systematical analysis of growth relationship and heredity differentia tion. The results showed that seven haplotypes were detetced. There were, 6 haplotypes in Guihzou population, 3 in Shaanxi population, and only 1 in Hunan population. The genetic diversity index indicated that the genetic diversity level was as follows： Guizhou〉Shaanxi 〉Hunan, but all of them were at a low level. Because of the geographical isolation, the gene flow was Nm〈1, and genetic differentiation was significant. However, it did not reach the level of population differentiation. Genes of Guizhou population differed with those of Hunan population in 140 000-350 000 years ago, and differed with those of Shaanxi in 120 000-300 000 years ago. The genes of Shanxi and Hunan population differed much later, about 20 000-50 000 years ago. Cryptic species of giant salamander might emerge in Guizhou.