极危物种蛇岛蝮隔离分化的分子生态学研究

Gloydius shedaoensis, a critically endangered snake species in China, is of great value for evolutionary studies due to its unique island distribution and significantly specialized morphology and behavior. However, its population suffered a serious decrease fifty years ago, and this might have led to increased risk of inbreeding. Therefore, it is essential to carry conservation genetics studies for the long-term preservation of this rare species. The current study aims to: 1) use conservation genetics tools to evaluate the level of the population health of Gloydius shedaoensis by estimating its genetic diversity level and inbreeding risk; 2) uncover the closest mainland relative of Gloydius shedaoensis and its distribution by conducting comparative molecular phylogeography of Gloydius taxa, which may guide ex-situ conservation of Gloydius shedaoensis when necessary; 3) calculate the divergence time between Gloydius shedaoensis and its closest mainland relative by the molecular calibration technique, and further evaluate the impact of geological events on the population history of Gloydius shedaoensis; 4) use molecular ecology methods to clarify the controversial classification between Gloydius shedaoensis and Gloydius shedaoensis qianshanensis, one of its potential close relatives, which may be a basis for judging their grades of protection. Therefore, using conservation genetics and molecular ecology approaches, our study will provide scientific guidance for the protection of this unique endemic snake species in China.

蛇岛蝮（Gloydius shedaoensis）为我国特有极危物种，因其独特的岛屿分布及显著特化的形态与行为具有极高学术价值。蛇岛蝮分布区狭小且数量稀少, 其种群曾遭受严重损失，易陷入"近交衰退"的危险境地。为蛇岛蝮种群的长远健康发展，借鉴现代分子生态学方法对其开展全面保护研究迫在眉睫。本研究拟（1）首先采用保护遗传学方法综合评价蛇岛蝮种群遗传健康水平，分析其遗传多样性水平及近交风险；（2）进一步利用分子谱系地理学方法确定蛇岛蝮的大陆直系近亲及分布点，为蛇岛蝮在特殊情况下进行迁地保护的地点选择提供遗传学依据；（3）利用分子钟定年技术进一步分析蛇岛蝮及其大陆直系近亲隔离分化历史，从历史角度分析评估环境变化对其种群产生的影响；（4）通过分子方法澄清蛇岛蝮与其大陆近缘类群千山蝮分类关系，为二者划分保护优先等级提供依据。本项研究将从分子生态学等多学科交叉角度为蛇岛蝮的保护规划提供重要科学指导。

蛇岛蝮（Gloydius shedaoensis）为我国特有极危岛屿物种，分布区狭小且数量稀少, 其种群曾遭受严重下降，具有潜在近交风险。为蛇岛蝮种群的长远健康发展，借鉴现代分子生态学方法对其开展保护遗传学研究迫在眉睫。本研究采用分子方法对该物种保护遗传学以及分子谱系地理进行了研究，研究结果显示，蛇岛蝮内部种群间基因流水平较高，蛇岛蝮种群内部没有明显遗传分化，蛇岛蝮遗传多样性水平较低，具有中等程度的近交风险。分子谱系学研究结果显示与蛇岛蝮关系最近的是分布在辽东半岛的千山蝮，其次是分布在东北大陆的岩栖蝮，三者具有相对最近的亲缘关系。分子定年结果显示，蛇岛蝮及其近缘类群的分化时间与渤海地区的海侵时间相一致，暗示蛇岛蝮及其近缘类群的进化分歧与第四纪海平面波动以及气候波动密切关联。本项研究增进了我们对蛇岛蝮种群现状以及其进化历史的了解，为蛇岛蝮的保护规划提供了重要科学依据。