Dissertation Research: Genetic Consequences of Variance in Gene Flow Components in Natural Populations of a Marine Angiosperm

自然植物种群遗传分化的进化原因还知之甚少。对基因流的估计对于区分选择和随机遗传漂移在产生种群结构中的相对作用是必要的。本研究旨在探讨基因流动、交配系统及选择对海洋被子植物结缕藻L种群遗传分化的贡献。初步数据表明，尽管鳗草种群有可能在海洋环境中进行远距离扩散和高周转率的殖民斑块，但它们在遗传上是不同的。对有效种群数量、交配系统和成虫迁徙对已实现的基因流的贡献的估计将被纳入现有的遗传分化预测模型。基因漂移对观察到的种群结构的贡献的可能性将通过1)对基因流动发生的空间规模的估计，以及2)旨在厌恶空间变化的选择的移植实验来评估。从这项研究中获得的信息将被用来评估关于授粉系统、基因流动和在陆地系统中建立的种群遗传结构的倾向的普遍性。

The evolutionary causes of genetic differentiation in natural plant populations are poorly understood. Estimates of gene flow are necessary to distinguish the relative roles of selection and random genetic drift in producing population structure. The purpose of the proposed research is to estimate the contributions of gene flow, the mating system and selection to population genetic differentiation in the marine angiosperm, Zostera marina L (eelgrass). Preliminary data suggests that eelgrass populations are genetically differentiated, despite the potential for long distance dispersal and high turnover rates of colonization patches in the marine environment. Estimates of the effective population size, the mating system and the contribution of adult migration to realized gene flow will be incorporated into existing predictive models of genetic differentiation. The possibility that genetic drift contributes to observed population structure will be evaluated by 1) estimates of the spatial scale over which gene flow occurs, and 2) transplant experiments designed to detest spatially varying selection. Information gained from this study will be used to evaluate the generality of tends regarding pollination systems, gene flow and population genetic structure established in terrestrial systems.