EAGER: Test for local adaptation of recombination rate

基因重组对许多遗传和进化过程至关重要，包括分离、DNA双链断裂的修复、有害突变的消除、适应和物种形成。先前的研究表明，基因重组的速度在个体和种群中有所不同，在许多物种中也受到温度和其他环境因素的调节。尽管进行了一百多年的研究，但还没有研究检验基因重组率是否表现出对当地环境的适应这一基本假设。这个项目将研究果蝇野生种群的变异，并识别正在经历快速选择驱动的重组率进化的基因组区域。这个新颖的项目是确定自然选择的第一步，这种自然选择在重组率上创造了适应和物种分化。此外，该项目还资助了与一所为少数族裔服务的高中的伙伴关系，并包括在K-16学校教授遗传学的课程开发。这个项目建立在几十年来对假黑腹果蝇野生种群的研究基础上，以提供关键的“第一眼”，看看重组率是否适应了当地种群，并可能为测试这种适应的性质打开了大门。拟议研究的主要目标将是比较几个自然种群内和几个自然种群之间的核苷酸序列变异与在恒定环境中测试时的重组率。群体间较高的重组率分化表明该表型已适应当地环境，而较低的重组率分化则表明该性状在整个物种范围内存在广泛的稳定选择。这项研究的第二个目标将是测试自然界中表现出的速率是否有时由于环境调节而在特定种群中最初是不适应的，以及在种群内发生适应以减轻由于对环境的可塑性而引起的不适应性速率。尽管这种“基因补偿”在遗传、适应和物种形成中的重要性无处不在，但这种“基因补偿”已经被推断用于其他性状，但从未被建议或测试过重组。

Genetic recombination is fundamentally important to many genetic and evolutionary processes, including segregation, repair of double-strand breaks in DNA, removal of detrimental mutations, adaptation, and speciation. Prior research has shown that rates of gene recombination vary among individuals and populations, and are also modulated by temperature and other environmental factors in many species. Despite being the subject of over a hundred years of investigation, no study has tested the fundamental hypothesis of whether gene recombination rates exhibit adaptation to local environments. This project will examine variation in wild populations of the fruit fly, Drosophila pseudoobscura, and identify genomic regions undergoing rapid selection-driven evolution in recombination rates. This novel project is the first step in identifying the kind of natural selection that creates adaptation and species divergence in recombination rates. Additionally this project funds a partnership with a minority-serving high school and includes curriculum development to teach genetics in K-16 schools. This project builds on decades of research on wild populations of Drosophila pseudoobscura to provide a critical "first-look" at whether recombination rates have adapted to local populations and potentially open the door to testing the nature of such adaptation. The primary goal of the proposed research will be to contrast variation within and between several natural populations of D. pseudoobscura in nucleotide sequence vs. recombination rate when tested in a constant environment. Significantly higher differentiation among populations in recombination rate would suggest that this phenotype has adapted to local environments, whereas lower differentiation in recombination rate would demonstrate that there has been broad stabilizing selection in this trait across the species range. The secondary goal of the research will be to test whether rates exhibited in nature are sometimes initially maladaptive in particular populations as a result of environmental modulation, and adaptation occurs within populations to mitigate the maladaptive rates induced by plasticity to the environment. Such "genetic compensation" has been inferred for other traits, but never suggested or tested with respect to recombination, despite its ubiquitous importance in inheritance, adaptation, and speciation.