Collaborative Research, RUI: The Evolution of Sex Ratio and Gender in Selfing vs. Outcrossing Clarkia spp. (Onagraceae)

开花植物进化出了各种确保授粉的机制。许多物种是异交，依靠昆虫来传递花粉，而另一些物种则是自花授粉(每朵花都会自己授粉)。异交祖先自交受精的进化通常也有类似的结果。例如，动物授粉的异交者通常比近缘的自花授粉物种产生更大的花和更高的每朵花的花粉与胚珠的比例。这项研究问：自然选择是否像预测的那样，在自交和异交物种之间产生更细微的遗传差异？几个预测将被检验，包括异交者比自交者更有可能在分配给男性和女性功能的资源之间表现出相反的关系。三对近缘关系密切的野花属异交和自交物种将就雄性和雌性生殖性状的遗传变异和基于遗传的相关性进行比较。将进行温室和田间实验，以检验异交种和自交种之间花卉性状独立进化的制约因素。10到12名本科生和1名博士后研究人员将接受进化论、植物育种和繁殖、统计分析和结果展示方面的培训。这项研究将有助于我们理解自然选择影响与交配系统相关的进化变化的潜力和局限性。

Delesalle9816256Flowering plants have evolved a variety of mechanisms that ensure pollination. Many species are "outcrossing", relying on insects to transfer pollen, while others are self-fertilized (each flower pollinates itself). The evolution of self-fertilization from outcrossing ancestors has often had similar outcomes. For example, animal-pollinated outcrossers often produce larger flowers and higher ratios of pollen to ovule production per flower than closely related self-fertilizing species. This study asks: Does natural selection operate as predicted to generate more subtle genetic differences between selfing and outcrossing species? Several predictions will be tested, including that outcrossers are more likely than selfers to exhibit an inverse relationship between the allocation of resources to male vs. female function. Three pairs of closely related outcrossing and self-fertilizing species in the wildflower genus Clarkia will be compared with respect to genetic variation in, and genetically based correlations among, male and female reproductive traits. Greenhouse and field experiments will be conducted to examine constraints on the independent evolution of floral traits in outcrossers vs. selfers.Ten to twelve undergraduate students and one post-doctoral researcher will receive training in evolutionary theory, plant breeding and reproduction, statistical analysis, and the presentation of results. This study will contribute to our understanding of both the potential and limits of natural selection to effect evolutionary changes associated with mating system.