OPUS: MCS: Is self-fertilization an evolutionary dead end? Artificial selection of a key outcrossing trait and its consequences in partially selfing populations

理解限制进化和适应的过程仍然是生物学中的一个主要问题。许多植物和动物进化出的特征使它们能够通过自花受精产生后代。然而，这种转变被认为是一条单行道，因为自花受精限制了阻止进一步进化的遗传变异。该项目将确定主要自花受精的植物是否可以重新进化为异交。高度异交和主要自交的猴花物种将比较其遗传变异和人工选择的花性状，决定自交率。该项目将使大学生参与进行独立的实验和分析遗传数据，并将为华盛顿州立大学的一门本科课程编制关于人工选择和遗传进化的新实验材料，在主要是自交的群体中，有限的遗传变异被认为是异交性状进化的主要限制。虽然预期近亲繁殖会导致有效种群规模和重组效率的下降，但有关其对适应性性状进化的影响的信息却很少。在主要是自交系的异交性状的再进化的限制表明，要么是遗传变异是有限的，或这样的反应是可能的，但不太可能发生。异交群体和自交群体的Mimulus guttatus。laciniatus和M.为了增加花药-柱头距离这一关键异交性状，将对小花进行5个世代的人工选择，并将确定实现遗传力。对照系和选择系在实验前后的合并全基因组群体测序将揭示选择对其基因组的比较效应。这种全基因组信息有可能将适应的限制与自花受精的遗传后果（即，该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Understanding the processes that limit evolution and adaptation remains a major question in biology. Many plants and animals evolve traits that allow them to produce offspring through self-fertilization. However, this transition is thought to be a one-way street because self-fertilization limits genetic variation which prevents further evolution. This project will determine whether plants that primarily self-fertilize can re-evolve to be outcrossing. Highly outcrossing and primarily selfing species of monkeyflower will be compared for their genetic variation and artificially selected for flower traits that determine the rate of selfing. The project will involve undergraduates in the conduct of independent experiments and the analysis of genetic data, and new laboratory materials will be developed on artificial selection and genetic evolution for an undergraduate course at Washington State University.Limited heritable variation in predominantly selfing populations is thought to be a primary constraint on the evolution of outcrossing traits. While declines in effective population size and the efficacy of recombination are expected with close inbreeding, there is scant information on their consequences for adaptive trait evolution. Constraints on the re-evolution of outcrossing traits in primarily selfing lineages suggest either that genetic variation is limiting or that such responses are possible but unlikely to occur. Outcrossing populations of Mimulus guttatus and selfing populations of M. laciniatus and M. micranthus will be subject to five generations of artificial selection for increasing the anther-stigma distance, a key outcrossing trait, and the realized heritability will be determined. Pooled whole-genome population sequencing of the control and selection lines before and after the experiments will reveal the comparative effects of selection on their genomes. This whole-genome information has the potential to critically link constraints on adaptation to the genetic consequences of self-fertilization (i.e., low nucleotide diversity and strong linkage disequilibrium).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.