羚牛的遗传多样性及其种群遗传结构分析

羚牛是亚洲大陆一种特有的大型珍稀动物，目前正面临着栖息地丧失、片段化和人类活动的严重威胁。为了有效地保护这种濒危动物，全面了解羚牛的种群结构、进化历史和整个分布区内遗传多样性的分布是至关重要的。本研究以mtDNA D-loop330bp基因片段为分子标记，比较分析了来自陕西秦岭、甘肃南部、四川岷山、邛崃山和云南贡山的40个样品的序列差异，根据分布特点将所采集到的羚牛分为3个地理单元，即秦岭、四川和云南。结果表明，在3个地理单元中存在4种单倍型，且地理单元间不存在共享单倍型，相互单倍型之间的平均序列差异为1.66％。进一步分析表明，3个地理单元间的基因流较低，存在着显的遗传分化 ，说明羚牛具有明显的系统地理分布格局。同时提出应将分布于秦岭山区、唐家河青川地区、天全以及云南贡山地区作为独立的管理单元分别加以保护。

Genetic Diversity and Population Genetic Structure of Takin (Budorcas taxicolor)

Takin ( Budorcas taxicolor ) is a large rare animal endemic to Asian continent. It belongs to Bovidae in Artiodactyla and mainly distributes in China and some locations of Burma, India, Nepal and Bhutan. Takin is currently threatened seriously by habitat loss, fragmentation and human activities. In order to develop adequate conservation and scientific management strategies for effectively protecting this endangered species, it is important to understand population genetic structure, evolutionary history and genetic diversity of takin. Based on mtDNA D-Loop 330 base pairs analysis, we investigated the population genetic structure, molecular phylogeography, and genetic diversity of 40 takins sampled from Qinling Mountains in Shaanxi Province, southern Gansu Province, Min Mountains and Qionglai Mountains in Sichuan Province, and Gong Mountains in Yunnan Province.According to sample distribution, they can be divided into three geographic units, i.e., Qingling, Sichuan and Yunnan. The results indicated that there were only 4 haplotypes in takin samples without sharing haplotype among three geographic units. The average divergence within the 4 haplotypes was 1.66%. Furthermore, the AMOVA(Analysis of Molecular Variance) analysis and phylogenetic trees also indicated that there was a significant genetic subdivision ( P <0.000 1)and relatively lower gene flow among geographic units. There was an obvious molecular phylogeographic pattern in takin samples. We suggested that the distribution pattern resulted from long-term geographical barriers and the considerable climatic fluctuation in Pleistocene. Thus, we also suggested that the four haplotypes (Qingling, Sichuan 1, Sichuan 2, and Yunnan) may be considered as 4 different management units and need to be conserved.