东亚槭属植物生物地理特征及竞争性杂交研究

Climate change is altering the natural systems across the globe. For the species, adaptive evolution is one of the most important responses to the changing environment and understanding the mechanism of adaption will help us to forecast the evolutionary trajectories of the species. For discovering the correlation between the environmental change and the adaptive evolution, the highly diversified genus Acer L. of East Asia was chosen as the model for investigating the adaptive evolution as well as their demographic history. Two subtopics of this study go to: (1) sequencing multiple genes to reconstruct phylogenetic trees of Acer and performing analyses of molecular dating, diversification-rate shifts, and biogeographic modeling to infer the speciation, and migration of East Asian maples; (2) separating the neutral and adaptive loci to perform the hybridization and introgression model tests and the demographic computation for the chosen sympatric species to test the adaptively competitive exclusion, which help to understand whether the sizes of adaptive/maladaptive gene pools varied due to adaptively competition through the process of asymmetric hybridization. These results will provide important bases for revealing how species in Asian continent response to the changing environment in this area.

气候变化持续的影响着全球的自然生态系统。适应性进化是物种应对气候变化的最重要方式，因此掌握物种对环境适应的机理可了解其未来的命运。本研究拟选择东亚槭属(Acer L.)物种作为研究材料，探讨环境变异与物种适应性进化的关联性。本研究分为两部分：（1）利用多基因定序对东亚槭属植物进行系统发育重建，并通过生物地理模型检测等方式，对东亚槭属植物的物种形成、迁徙与扩散等进行探讨；（2）挑选不同进化分支下共域分布的物种，分别以中性基因与适应性基因进行检测，分析杂交与基因渗入及物种基因库变化，揭示共域物种间的适应性竞争关系。本研究将为深入理解亚洲大陆物种对气候变化的应对提供基础。

东亚地区物种在末次冰期的迁徙与避难情况较欧美物种更为复杂，在绘制全球生物地理地图的大背景下，了解东亚地区物种的进化历程就显得尤为重要。本项目以现代分布中心主要位于东亚地区的槭属物种为研究材料，探讨气候变化下东亚槭属物种的进化历史。.本项目利用一代测序、二代测序技术对东亚槭属物种的物种形成、迁徙与扩散、共域槭属物种间的适应性竞争关系等进行了探讨。结果显示：我国西南地区可能是东亚槭属物种的起源地及末次盛冰期时的主要的潜在避难所之一；现代分布于欧美地区的槭属物种可能是从亚洲多次迁徙而来，且东海陆桥的抬升与下降直接影响着东亚槭属物种的局地扩散；东亚地区亚热带槭属物种存在多次往同纬度高海拔地区扩散的现象；东亚槭属物种现代分布区范围较末次盛冰期时出现向北扩张，未来的分布区范围可能出现两端收缩趋势；共域分布于我国长江流域的罗浮槭与青榨槭可能存在杂交。本研究为揭示北温带乔木树种的适应性进化机制提供了一笔理论依据，并为槭属种质资源保护与利用提供了参考。