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

Delesalle9816256开花植物已经进化出多种确保授粉的机制。 许多物种是“异型杂交”，依靠昆虫传递花粉，而其他物种则是自花授粉（每朵花都自行授粉）。 异型杂交祖先的自体受精进化往往会产生类似的结果。 例如，与密切相关的自花受精物种相比，动物授粉的异型杂交通常会产生更大的花朵，并且每朵花的花粉与胚珠产量的比率更高。 这项研究提出的问题是：自然选择是否如预测的那样在自交和异交物种之间产生更微妙的遗传差异？ 一些预测将得到测试，包括异型杂交者比自交者更有可能在雄性与雌性功能的资源分配之间表现出反比关系。 将比较克拉克氏野花属中三对密切相关的异交和自花受精物种的遗传变异以及雄性和雌性生殖性状之间基于遗传的相关性。 将进行温室和田间实验，以检验异交和自交花性状独立进化的限制。十到十二名本科生和一名博士后研究员将接受进化理论、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了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.