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，最早是由Dobzansky在1937年提出的，在物种形成的研究中仍然是一个有争议的话题。强化在许多密切相关的生物体中得到了越来越多的测试，然而，只有一项研究测试了它在植物物种形成中的作用，没有研究直接衡量自然选择在面对持续的基因交换时增加生殖隔离的程度。我们将使用比较和实验的方法来研究强化在植物属Mimulus中的作用，Mimulus是进化和生态学的模式系统。在具有重叠范围的密切相关的物种对之间观察到增加的花的分歧，这一模式与加强一致。由该奖项资助的研究将解决观察到的花卉分化是否与交配系统变化有关，并直接衡量对增加田间生殖隔离的花卉性状的选择。温室中将对16个物种对的多个种群的自花授粉率进行量化，并将使用分子工具在田间确认自然种群的自花授粉率。在这些研究之后，将进行基于田间的基因选择实验，以衡量对增加生殖隔离的花卉性状的选择。这项研究将对一种被认为在新物种形成中发挥重要作用的机制构成强有力的考验。它既有很强的学术价值，也有可能提高公众对进化过程的理解，从而产生更广泛的影响。该项目的其他更广泛的影响包括对将参与研究的两名本科生的指导，以及对一名博士生的支持。

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.