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

自然选择理想地导致生物体很好地适应了他们的环境。 然而，对于生活在各种环境条件下的物种来说，这种微调很难实现。 从物种分布区的中心迁移到边缘，可以引入适合中心环境但不适应边缘环境的基因。 自然选择和基因流的反作用力将被调查的植物物种，范围从海平面到海拔1500米的太平洋斜坡在哥斯达黎加。复制花园将建立在海拔范围内，使用来自整个范围的植物，其生物适应性将在每个环境中进行评估。 “主场优势”提供了证据，证明自然选择在不同的地点促进了不同的基因。 在第二组实验中，将使用分子标记来估计物种海拔范围内的基因流量。该项目解决了种群生物学的一个核心问题，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用的比较。 将为至少8名本科生和3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.