RUI: Gene flow, selection, and maintenance of mating system diversity on an ecological gradient

自然选择的理想结果是产生能够很好地适应环境的有机体。然而，对于生活在广泛环境条件下的物种来说，这样的微调是很难实现的。从物种范围的中心到边缘的迁徙可能会引入适合于中心环境但不适应外围环境的基因。将针对哥斯达黎加太平洋斜坡上从海平面到海拔1500米的一种植物物种，研究自然选择和基因流动的反作用力。将在不同的海拔范围内建立复制花园，使用来自该范围内的植物，其生物适合性将在每种环境中进行评估。“主场”优势提供了自然选择在不同部位促进了不同基因的证据。在第二组实验中，分子标记将被用来估计物种海拔范围内的基因流数量。该项目解决了种群生物学中的一个中心问题，即基因流动在多大程度上抵消了自然选择。它发生在山地热带森林中，提供了保护相关性，并与温带系统的结果进行了有益的比较。将为至少八名本科生和三名学士后学生提供培训机会。

Natural selection ideally results in organisms that are well-adapted to their environments. However, such fine-tuning is difficult to attain for species that live over a broad range of environmental conditions. Emigration from the center of the species range to the margins can introduce genes that are suited for environments at the center but maladapted for environments at the periphery. The counteracting forces of natural selection and gene flow will be investigated for a plant species that ranges from sea level to 1500 meters elevation on the Pacific Slope in Costa Rica. Replicate gardens will be established across the range of elevations, using plants that originate from across the range, whose biological fitness will be evaluated in each environment. A 'home field' advantage provides evidence that natural selection has promoted different genes at different sites. In a second set of experiments, molecular markers will be used to estimate the amount of gene flow across the elevational range of the species. The project addresses a central question in population biology, the extent to which gene flow counteracts natural selection. It takes place in montane tropical forests, providing conservation relevance and a useful comparison to results from temperate systems. Training opportunities will be provided for at least eight undergraduate and three post-baccalaureate students.