Recombination rate variation and evolution

摘要 减数分裂重组对于减数分裂期间染色体的适当分离是必要的，并且在产生染色体的过程中是必要的。 通过等位基因的改组来实现种群的遗传多样性。重组事件数量的变化， 或重组率，因此可以通过减数分裂失败对个体生物健康产生影响， 通过影响选择的有效性来影响种群适应度。然而，重组率的变化 记录在基因组中，在种群和物种中。尽管在编目方面取得了进展 重组率的变化，如何以及为什么重组率的变化仍然在很大程度上未知。的目标 我的研究计划是调查重组率变化的遗传和环境原因， 重组率变异对基因组进化的影响。在接下来的五年里，我的实验室将使用 实验进化和基因组学在酵母菌探索三个主要问题。首先， 重组景观在短时间尺度上的变化？我们用全基因组测序 构建葡萄汁酵母多个群体的全基因组重组率。我们寻求 确定启动重组的双链断裂如何作为交换或非交换被修复 基因转换事件，以及这两种类型的事件如何在种群之间保守或分化。 这将是第一个研究多个种群中两种类型重组事件的进化， 提供了一个前所未有的观点的机制，潜在的复合率变化。第二，我们 研究对新环境的适应如何改变重组率。塑性膨胀率 多年来一直与温度和其他环境因素的变化有关， 影响重组率进化的环境适应（或反之亦然）缺失。我们会进化 耐寒S.在实验室中进行葡萄囊种群的耐热性研究，并使用全基因组测序 以确定重组率的任何变化或交叉和非交叉基因转换的分布 由于适应温度而发生的事件。最后，我们要探索重组率 影响杂交后基因组中渐渗的分布和持久性。我们 从两个不同的S.部分生殖隔离的悬雍垂 由于对弱， 负上位互作我们将比较进化种群中基因渗入的分布， 重组图，以更好地了解是什么力量在杂交后的世代中塑造基因组。 总的来说，我的研究将利用与易处理的酵母系统合作的好处， 测试长期存在的关于重组如何以及为什么随着时间而变化的假设。

Abstract Meiotic recombination is necessary for the proper segregation of chromosomes during meiosis, and in creating genetic diversity in populations through the shuffling of alleles. Changes in the number of recombination events, or recombination rate, can thus have impacts on individual organismal health via meiotic failure, and on population fitness by influencing the efficacy of selection. And yet, variation in recombination rate has been documented across the genome, and among populations and species. Despite progress in cataloguing recombination rate variation, how and why recombination rate changes remains largely unknown. The goal of my research program is to investigate the genetic and environmental causes of recombination rate variation, and the consequences of recombination rate variation on genome evolution. Over the next five years, my lab will use experimental evolution and genomics in Saccharomyces yeast to explore three main questions. First, how does the recombination landscape change over short time scales? We are using whole genome sequencing to construct genome wide recombination rates in multiple populations of Saccharomyces uvarum. We seek to identify how the double strand breaks that initiate recombination are repaired as crossover or non-crossover gene conversion events, and how these two types of events are conserved or divergent between populations. This will be the first study to examine evolution in both types of recombination events in multiple populations, offering an unprecedented view of the mechanism underlying recombination rate variation. Second, we are investigating how adaptation to a new environment alters recombination rate. Recombination rate plasticity has been linked to changes in temperature and other environmental factors for many years, but explicit tests of environmental adaptation influencing recombination rate evolution (or vice versa) are missing. We will evolve cold tolerant S. uvarum populations in the lab for increased thermotolerance, and use whole genome sequencing to identify any shifts in recombination rate or the distribution of crossover and non-crossover gene conversion events that occur as a result of adaptation to temperature. Finally, we’re exploring how recombination rate influences the distribution and persistence of introgression in the genome following hybridization. We are evolving admixed strains from 2 diverging populations of S. uvarum with partial reproductive isolation to test the hypothesis that introgression is reduced in regions of low recombination due to selection against weak, negative epistatic interactions. We’ll compare the distribution of introgression in evolved populations to recombination maps to better understand what forces shape genomes in the generations after hybridization. Overall, my research will leverage the benefits of working with the tractable Saccharomyces system to empirically test longstanding hypotheses of how and why recombination changes over time.