沙漠孑遗植物唐古特白刺的种群遗传结构、区域分化和动态历史研究

极端环境下物种遗传分化和种群动态历史的研究是近年来进化生态学领域十分重要、也是最受关注的一个热点，其结果对于理解物种进化历史和成种机制具有重要意义。目前，关于我国沙漠极端生境下植物物种的谱系分化和种群动态历史仍然缺乏统一认识。白刺属（蒺藜科）为古老的第三纪孑遗类群，其中唐古特白刺是我国干旱沙区分布最广、也是沙漠灌木中最具代表性的一个种，属于中国特有种。本项目应用多个cpDNA序列标记、RAD-seq简化基因组测序技术和生态位模拟方法，分析唐古特白刺的种群遗传结构和区域分化特征，追踪第四纪以来种群的迁移/扩张历史过程，尤其是从基因组水平上探讨种群大小变化、谱系分化等近期种群动态历史事件及其影响因素，阐明第四纪气候波动以及我国北方干旱沙漠气候的形成和演变对其种群迁移/扩张和分化的影响，揭示种群遗传结构形成的历史原因和过程。研究结果对于深入认识沙漠植物的进化历史和多样性形成机制具有重要理论意义。

Population structure and demographic history of species in extreme environments is a very important and attractive research focus in evolutionary ecology in recent years, and its research results play a significant role to understand evolutionary history and formation mechanism of species. Up to now, there is still a lack of a unified realization on phylogenetic diversification and demographic dynamic history of plant species in the extreme desert environments of northwestern China. Nitraria tangutorum, a endemic specis in China, belonging to the genus Nitraria L. (Zygophyllaceae) which is tertiary relics in desert areas, is one of the most widely distributed species in sandy areas of China. It is also the most representative taxon of desert shrubs. In this project, we will integratedly use multiple chloroplast DNA sequences, restriction-site associated DNA sequencing technology, and Ecological niche modeling to survey the population genetic structure and regional-scale differentiation of N. tangutorum, trace the expansion/recolonization of populations since the Quaternary. Especially, our study highlights the more recent population demographic history such as effective population size, phylogenic divergence, and their influencing factors revealed by genome, and subsequently, elaborates the effects of the Quaternary climate oscillations and the desert climate changes in north China on migration, expansion, and differentiation of the desert plant. This study will reveal the historical reasons and process of the genetic structure formation of N. tangutorum. The results will be of significance to understand the evolutionary history and diversification mechanism of desert plants in extreme environments.