How recombination alters drift and selection in the genome

重组如何改变基因组中的漂移和选择 ** 我的研究计划调查遗传变异的产生和可用性如何与漂移和选择相互作用，以影响进化。两个基本过程产生了为进化提供燃料的变异：突变和重组。突变产生新的变异，重组将突变改组成新的组合。在交配过程中，重组将不同个体中发生的有益突变聚集在一起，增加了选择的有效性。类似地，重组将附近的有益突变与有害突变分开，否则有害突变会干扰选择修复适应性变化的能力。有趣的是，有证据表明重组的速率在基因组中是不同的。这意味着基因组区域的选择可能或多或少有效，这取决于重组的速率。令人惊讶的是，很少有关于基因组中重组率变异的研究，主要是因为重组很少发生;每1000万个位点中不到一次。幸运的是，基因组革命提供了在分子尺度上观察重组所需的技术。我建议调查的变化，重组及其后果的适应模式衣藻。在我的建议中，我描述了三个互补的短期目标：*1。我将通过对重组株系的基因组进行测序来识别数千个重组事件，从而探索重组率如何以及为什么在个体之间和整个基因组中变化。我将研究基因组生物学的哪些方面最能预测重组率。这项工作将产生任何物种中重组率变化的最详细的特征之一。2.我将使用重组率变异的精细比例图来测试重组是否减少了选定突变之间的干扰。我预计重组率高的区域会适应得更快，而重组率低的区域会积累有害的突变。在这个框架中，我将研究蛋白质编码突变，碱基组成和基因组大小的选择强度。3.我将扫描自然基因组序列，寻找控制本地适应性状的基因岛。通过仔细的实验室分析，我将把赋予适应当地环境的基因和性状联系起来，并量化自然界中塑造微生物种群的因素。只有通过结合重组和突变的直接测量，才能进行我建议的工作。该项目将全面描述产生遗传变异的力量，促进详细了解适应如何在遗传水平上表现出来。

HOW RECOMBINATION ALTERS DRIFT AND SELECTION IN THE GENOME******My research program investigates how the generation and availability of genetic variation interacts with drift and selection to influence evolution. Two fundamental processes generate the variation that fuels evolution: mutation and recombination. Mutation creates new variants, and recombination shuffles mutations into new combinations. During sex, recombination brings together beneficial mutations that have occurred in different individuals, increasing the effectiveness of selection. Similarly, recombination breaks apart nearby beneficial from harmful mutations that would otherwise interfere with the ability of selection to fix the adaptive changes. Interestingly, there is evidence that the rate of recombination varies across the genome. This means that selection in regions of the genome may be more or less effective, depending on the rate of recombination. Surprisingly, there are few studies of recombination rate variation in the genome, primarily because recombination occurs so rarely; less than once in every 10 million sites. Fortunately, the genomic revolution offers the technology needed to observe recombination at the molecular scale. I propose to investigate variation in recombination and its consequences for adaptation in the model alga Chlamydomonas reinhardtii. In my proposal I describe three complementary short-term objectives:******1. I will explore how and why the rate of recombination varies between individuals and across the genome by sequencing the genomes of recombinant lines to identify thousands of recombination events. I will examine what aspects of genome biology best predict the rate of recombination. This work will generate one of the most detailed characterizations of recombination rate variation in any species.******2. I will test whether recombination reduces interference between selected mutations using the fine-scale map of recombination rate variation. I expect that regions with high recombination will adapt more quickly, while regions with low recombination will accumulate harmful mutations. In this framework, I will examine the strength of selection on protein-coding mutations, base composition, and genome size. ******3. I will scan natural genome sequences for islands of genes that control locally adapted traits. Using careful laboratory assays I will link the genes and traits that confer adaption to the local environment and quantify the factors that shape microbial populations in nature.******Only by incorporating direct measurement of recombination and mutation can the work I propose be conducted. This project will provide a comprehensive description of the forces that generate genetic variation, facilitating detailed understanding of how adaptation manifests at the genetic level.