Dissertation Research:Speciation is Reinforced by Natural Selecion in Plants: A Test Within The Genus Mimulus

增加生殖隔离的选择，称为强化，是由Dobzhansky于1937年首次提出的，在物种形成研究中仍然是一个有争议的话题。然而，只有一项研究测试了强化在植物物种形成中的作用，而且没有研究直接测量了面对持续的基因交换，增加生殖隔离的自然选择。比较和实验的方法将被用来检查在植物属Mimulus，在进化和生态模式系统中的强化作用。在亲缘关系密切的种对之间，分布范围重叠，花的分化增加，这种模式与强化一致。由该奖项资助的研究将探讨观察到的花的分化是否与交配系统的变化有关，并直接测量在田间增加生殖隔离的花性状的选择。在温室中对16个种对的多个群体的自花授粉率进行量化，并利用分子工具在田间确认自然群体的自花授粉率。这些研究之后将进行一项基于田间的基因型选择实验，以测量对增加生殖隔离的花性状的选择。这项研究将对一种被认为在新物种形成中起重要作用的机制进行有力的检验。它不仅具有强大的智力价值，而且由于它有可能提高公众对进化过程的理解，因此具有强大的广泛影响。该项目的其他更广泛的影响包括指导两名将参与研究的本科生，并支持一名博士生。

Selection for increased reproductive isolation, termed reinforcement, was first proposed by Dobzhansky in 1937 and remains a controversial topic in the study of species formation. Reinforcement is increasingly being tested in many closely related organisms, however, only a single study has tested its role in plant species formation and no study has directly measured natural selection for increased reproductive isolation in the face of ongoing gene exchange. Comparative and experimental methods will be used to examine the role of reinforcement in the plant genus Mimulus, a model system in evolution and ecology. Increased floral divergence was observed between closely related species pairs with overlapping ranges, a pattern consistent with reinforcement. Research funded by this award will address whether the observed floral divergence is associated with mating system shifts and directly measure selection on floral traits that increase reproductive isolation in the field. Self-pollination rates of multiple populations of 16 species pairs will be quantified in the greenhouse, and molecular tools will be used to confirm self-pollination rates in natural populations in the field. Those studies will be followed by a field-based genotypic selection experiment to measure selection on floral traits that increase reproductive isolation. This research will constitute a strong test of a mechanism that is thought to play an important role in the formation of new species. It will have both strong intellectual merit and, because it will have the potential to improve public understanding of the evolutionary process, strong broader impacts. Other broader impacts of this project include mentoring of two undergraduate students who will participate in the research, and support for a doctoral student.