中文摘要
本项目以适应性调节的资源垄断假说为零假设,以我国热带地区浮游生物关键种类—大型枝角类盔型溞为对象,根据景观遗传学的框架,结合第二代测序技术和传统中性标记,利用SSR和包含编码区及非编码区的SNP位点,研究空间要素下不同水系连接水平上的水库中盔型溞的现生种群和休眠种群的遗传多样性与遗传结构,分析盔型溞在区域水平上的遗传多样性与遗传结构空间分化特征,通过空间统计方法分析基因流和环境选择在盔型溞种群遗传多样性与结构分化中的作用;对遗传分化较大的种群进行竞争和生境适应性交叉对比实验,测定反映适应性性状的种群繁殖参数,检验适应性对种群分化的影响;利用实验测定的种群参数和野外种群遗传估计参数,建立种群遗传结构的动态模型,模拟和预测不同景观条件下种群遗传结构的变化以及基因流与环境选择的作用;评估资源垄断假说解释热带地区枝角类种群遗传结构分化的有效性,阐明热带地区水库大型枝角类遗传多样性的维持机制。
英文摘要
We use the local adaptation mediated resource monopolization hypothesis (DeMeester et al., 2002) as a hypothesis, and investigate population genetic differentiation of Daphnia galeata, a keystone species of tropical Cladocera in reservoirs. Following the framework of landscape genetics, we obtain and analyze its spatial structure of population genetics by applying the next generation sequencing techniques of genomics for SNP-based markers covering coding and non-coding regions and neutral markers of microsatellites. By using spatial statistics like Moran’s Eigenvector Map analysis, we reveal the roles of gene flow with functional connectivity and environmental selection in genetic diversity and differentiation of the population, and difference in genetic information of active populations in water columns and dormant populations in the surface sediments. A series of life history experiments for reciprocal cultures and competition experiments between differentiated populations are conducted to test local adaptation by comparing functional traits of reproduction (including intrinsic growth rate and the age of the first reproduction). We apply simulation models of CDPOP and IBDSim to simulate and predict the changes of genetic differentiation and diversity under different scenarios of functional connectivity and population demography in the studied reservoirs. Finally, we are able to evaluate the efficiency of the monopolization hypothesis in explaining Cladocera species in large tropical reservoirs, and infer the potential maintaining mechanisms of genetic diversity and genetic structure in tropical Cladocera.
