The Evolution of Dioecy and Sexual Dimorphism: An Integrative Approach Using a Gynodioecious Strawberry

小行星9707247 在许多谱系中，雌雄同体的祖先独立地进化出了单独的雄性和雌性开花植物（diophthalmus），导致进化生物学家得出结论，这种转变是生物学的一个中心问题。然而，我们并不完全了解这种转变是如何发生的。 一个密集的模型理论预测，女性和两性人的群体是一个中间步骤，以dioderma。雌性的存在预计会导致两性人的选择，使其在性别上变得更男性，如果存在某些遗传条件，那么雌雄同体就可以进化。 这项研究将通过描述一个模型系统的遗传结构，野生草莓（Fragaria virginiana）， 在选择性环境的一个基本方面（雌性的频率），表现出过渡性的育种系统和种群变异。通过描述野生草莓四个种群（雌性频率连续体两端各两个）生殖性状（花粉产生、坐果和花瓣）之间的遗传关系，本研究不仅揭示了选择反应的潜力，而且还将评估生殖进化理论模型的假设和稳健性。此外，种群间的比较将产生关于遗传参数的恒定性以及这种恒定性对进化变化的影响的信息。 这项研究将提供有关生殖系统进化的信息，这些信息与进化生物学基本相关，因为所有生物体都面临类似于这里研究的生殖分配决策的分配决策。植物生殖系统与许多其他系统一样，器官在功能和结构上是同源的，因此必然具有共同的发育和遗传基础。了解基因结构对基因表达的限制， 个体表型和两性异形的进化是进化生物学的一个重要方面。此外，种群间的比较将提供遗传结构不稳定性的信息，并将为检验数量遗传学应用于进化问题的假设做出重大贡献。

9707247 Ashman Separate male and female flowering plants (dioecy) have evolved from hermaphrodite ancestors independently in numerous lineages, leading evolutionary biologists to conclude that such a transition is a central problem in biology. However, we do not have a complete picture of how this transition occurs. An intensively modeled theory predicts that populations with females and hermaphrodites are an intermediate step to dioecy. The presence of females is expected to result in selection on hermaphrodites to become more male in gender, and if certain genetic conditions exist then dioecy can evolve. This research will address the potential for dioecy to evolve by characterizing the genetic architecture of a model system, the wild strawberry (Fragaria virginiana), that exhibits a transitional breeding system and among-population variation in a fundamental aspect of the selective environment (the frequency of females). By characterizing the genetic relationships among reproductive traits (pollen production, fruit set, and petals) in four populations of wild strawberry (two from each end of the female frequency continuum), this research will not only reveal the potential for response to selection, but it will also evaluate the assumptions and the robustness of theoretical models of reproductive evolution. Furthermore, among-population comparisons will yield information on the constancy of genetic parameters and the consequences of such constancy for evolutionary change. This research will provide information on the evolution of reproductive systems, information that is fundamentally relevant to evolutionary biology because all organisms face allocation decisions similar to the reproductive allocation decisions studied here. Plant reproductive systems are like many other systems where organs are functionally and structurally homologous, and thus necessarily have a shared developmental and genetic basis. Gaining an understanding of the constraints imposed by genetic architectur e on the evolution of individual phenotype and sexual dimorphism is an essential aspect of evolutionary biology. Furthermore, comparisons among populations will provide information on the lability of genetic architecture and will make a significant contribution to testing the assumptions of quantitative genetics as applied to evolutionary questions.