DISSERTATION RESEARCH: Empirical, theoretical, and comparative tests of major hypotheses for the recurrent evolution of self-fertilization

论文研究：自体受精循环进化主要假设的实证、理论和比较测试

• 批准号: 1601545
• 负责人: Jeremiah Busch
• 金额: $ 1.01万
• 依托单位: Washington State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1601545&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Empirical; theoretical; comparative; DISSERTATION; RESEARCH; Empirical; theoretical; comparative

The goal of this project is to evaluate the underlying mechanisms that drive the evolution of the ability for flowering plants to self-fertilize. This goal will be accomplished by measuring the rate at which lineages transition from outcrossing to self-fertilizing in the mustard family, a diverse and agriculturally important group. Flowering plants display an incredible breadth of variation in flower size, shape, and color that is generally attributed to the co-evolution of flowering plants and pollinators. Considering the potentially important role of cross-pollination in evolution, it is surprising that the shift to self-fertilization is one of the most common evolutionary transitions in flowering plants. Despite decades of work on this subject, it is still not clear what drives the initial spread of selfing and tests of the leading hypotheses explaining this pattern are rare. One reason for this is that a series of rapid changes in other floral traits occur in response to selfing, which then act to obscure traditional methods of comparative inference. Additionally, the project will result in the training of graduate and undergraduate students.In flowering plants, shifts from outcrossing to selfing and from diploidy to polyploidy are common and are thought to occur in concert An association between selfing and polyploidy can occur through three non-mutually exclusive pathways. First, polyploidization could act as a filter, limiting the founding of new populations to those that originate from a self-compatible progenitor. Second, polyploidization could provide strong reproductive assurance resulting in the joint transition of mating system and ploidy. Finally, polyploidization could create a favorable environment for the spread of selfing after the population is established. This research estimates the transition rates of these three pathways in the Brassicaceae by assembling a database of mating system and ploidy data and extending a multi-state comparative model. These estimates will be used to evaluate the relative importance of reproductive assurance in the spread of selfing in neopolyploids. The model will show why simultaneous transitions to selfing and polyploidy are relatively rare in Brassicaceae and other families with sporophytic self-incompatibility (SI). The theoretical framework will be extended to explain why such SI systems can survive extreme population bottlenecks associated with polyploidy and island colonization.

该项目的目的是评估开花植物自我施用能力的演变的基本机制。该目标将通过衡量谱系从脱落到自我利用的谱系的速率来实现，这是一个多样化和农业重要的群体。开花植物表现出令人难以置信的花朵，形状和颜色变化的广度，这通常归因于开花植物和授粉媒介的共同进化。考虑到交叉授粉在进化中的潜在重要作用，令人惊讶的是，自我施用是开花植物中最常见的进化转变之一。尽管在这个主题上进行了数十年的工作，但仍不清楚是什么驱动了自我自我传播的最初传播和解释这种模式的主要假设的测试。这样做的一个原因是，其他花卉特征的一系列快速变化是响应自变的，然后起作用，这些变化掩盖了传统的比较推断方法。此外，该项目将导致毕业生和本科生的培训。在开花植物中，从脱落到自我的转变，从二倍体到多倍体，并且被认为是通过三种非局部排斥的途径在自我的结合中发生的。首先，多倍体化可以充当过滤器，将新人群的建立限制在源自自我兼容的祖细胞的人群中。其次，多倍体化可以提供强大的生殖保证，从而导致交配系统和倍增性的关节过渡。最后，多倍体化可以在建立人口后的自我传播中创造一个有利的环境。这项研究通过组装配合系统和倍增性数据并扩展多状态比较模型来估计胸肌中这三个途径的过渡速率。这些估计将用于评估生殖保证在新多倍体中自我传播中的相对重要性。 该模型将表明为什么在甘蓝科和其他具有孢子性自我不相容性（SI）的家庭中同时向自我和多倍体过渡相对较少。将扩展理论框架，以解释为什么这种SI系统可以在多倍体和岛屿定植相关的极端种群瓶颈中生存。