金沙江河谷地区岩羊种群遗传多样性分析

Genetic Diversity Analysis of Pseudois nayaur Population in Jinsha River Valley Area

岩羊为国家Ⅱ级保护动物。目前,由于人类活动范围日益扩大,其栖息地遭到了不同程度的破坏,岩羊种群数量和分布范围呈明显下降趋势。为了及时制定科学的保护策略必须了解它们的种群遗传结构。本文以粪便为研究材料,对来自金沙江河谷地区林线以上岩羊和林线以下矮个子岩羊共4个地理种群的169份有效样品进行线粒体CR全序列分析,共检测出210个变异位点,定义了4种单倍型,单倍型多样性为0.68,核苷酸多样性为0.0242,显示种群整体遗传多样性水平较低。基于最大简约法构建的系统发育树中,金沙江河谷地区的4个地理种群被划分到四川种群的2个亚分支中,但云南曲宗贡的部分岩羊和四川竹巴笼的矮个子岩羊单倍型存在共享现象。根据分子钟计算,林线上下岩羊分化时间在39～32万年前,在中更新世早中期（105～36万年前）气候影响下,导致岩羊在金沙江河谷高低海拔之间相互迁移。对于岩羊在历史上所表现出的潜在迁徙能力,我们建议将白马雪山自然保护区到竹巴笼自然保护区之间的金沙江河谷地区作为岩羊和矮个子岩羊的栖息地整体保护。

Pseudois nayaur had been listed as an endangered wild animal by the International Union for Conservation of Nature. It is belonging to the second grade national protected animal in China. In recent years, human activities including logging, hunting, road building and overgrazing of pastures had caused significant decrease of P. nayaur population. Under-standing the genetic diversity status and the population structure in different geographic population of P. nayaur would contribute to the development of systematic conservation strategies. A total of 226 faece samples were obtained from Jinsha River Valley and 169 sequences of control region belonging to 4 haplotypes were amplified. The population of the P. nayaur showed a relatively high haplotype diversity but low levels of nucleotide diversity （ h = 0.68, π = 0. 0242）. We concluded that the P. nayaur population of Jinsha River Valley had a very low genetic diversity. The phylogenetic tree constructed based on maximum parsimony method suggested that the four geographical populations in Jinsha River valley were clustered into two subclades of Pseudois nayaur szechuaneruis. At the same time, all samples of dwarf P. nayaur from Batang county and the partial P. nayaur from Quzonggong sampling station were found to share the same haplotype. The molecular clock analysis suggested that the dwarf P. nayaur and the P. nayaur were diverged from 0.39 Mya to 0.32 Mya. It appeared that the evolutionary history of P. nayaur, such as divergences and population dispersal might be strongly affected by climate fluctuation in the early mid-Pleistocene （1.05～0.36 Mya）. Based on the migration ability of P. nayaur, we suggested that from Baima Mountain Nature Reserve to Zhubalong Nature Reserve along Jingsha River Valley should be conserved as integrated habitat for these populations.