高原鼠兔四个地理种群的遗传多样性与遗传分化

采用7 个多态微卫星DNA 标记分析了4 个高原鼠兔地理种群(海晏种群、西大滩东种群、西大滩西种群和昆仑山种群)的遗传多样性和遗传分化。采用多态信息含量(PIC)、期望杂合度(H_e )、观测杂合度(H_o)、基因流(N_m )和基因分化系数(F_st )对种群及物种的遗传多样性水平进行分析;计算各种群间的遗传距离(GD)、遗传相似度(GI)以及遗传距离与地理距离的相关系数,并进行UPGMA 聚类分析。研究结果显示,高原鼠兔的遗传多样性在小哺乳动物中处于较高水平, 其H_e 和H_o 的平均值分别为0. 5332 和0. 6003, 其F_st 为0. 0975,即有9. 75% 的变异存在于种群之间,即变异主要存在于种群内部。4 个种群间的杂合度与多态信息含量均无显著差异,说明它们的遗传多样性水平基本相当。海晏种群与其余3 个种群的遗传分化均达到了中度分化水平(F_st = 0.1043),而另3 个种群间几乎没有分化(F_st = 0. 0253)。Mantel test 结果表明地理距离与遗传距离间没有显著的相关性。

Genetic diversity and differentiation in four natural populations of plateau pika (Ochotona curzoniae)

The plateau pika (Ochotona curzoniae) has a widespread distribution over the high alpine grassland of the Qinghai-Tibet Plateau of People's Republic of China.It is one of the most dominant small mammals and plays an important role in keeping the balance of the alpine meadow ecosystem. The aim of this paper was to investigate the level of genetic diversity and also to test the hypothesis of IBD (isolation by distance) for this old species. Samples of plateau pikas were collected from four natural populations (Haiyan,Xidatan E, Xidatan W and Kunlunshan populations). Genetic diversity and differentiation were assessed with seven polymorphic microsatellite markers. The genetic diversity of plateau pika was comparatively higher than that for some other small mammals (H_o = 0. 6003, H_e = 0.5332). The majority of genetic variation occurred within populations (F_st = 0.0975). The levels of genetic diversity of the four populations were similar. High genetic differentiation was encountered between Haiyan population and the other three (F_st = 0.1043)probably due to the long distance between them. However, the results of mantel test showed that there was no significant correlation between geographical distance and genetic distance.