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、有害突变的去除、适应和物种形成。先前的研究表明，基因重组率在个体和种群之间有所不同，并且在许多物种中也受到温度和其他环境因素的调节。尽管基因重组率是否表现出对当地环境的适应性这一基本假设已经被研究了一百多年，但还没有研究证实这一假设。该项目将研究果蝇（Drosophila pseudobscura）野生种群的变异，并确定在重组率中经历快速选择驱动进化的基因组区域。这个新颖的项目是确定自然选择在重组率中产生适应和物种分化的第一步。此外，该项目还资助了与一所少数民族高中的合作，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伪眼果蝇野生种群的研究基础上，为重组率是否适应当地种群提供了关键的“第一眼”，并有可能为测试这种适应的本质打开大门。拟议研究的主要目标是对比在恒定环境中测试时，假盲蝽的核苷酸序列和重组率在几个自然种群内部和之间的差异。群体间重组率的显著高分化表明该表型已经适应了当地环境，而重组率的低分化表明该性状在整个物种范围内存在广泛的稳定选择。该研究的第二个目标是测试在自然界中表现出的速率是否在特定种群中最初由于环境调节而表现出不适应，并且种群内部发生适应以减轻由环境可塑性引起的不适应速率。尽管这种“遗传补偿”在遗传、适应和物种形成中具有普遍的重要性，但在其他性状中已经推断出了这种“遗传补偿”，但从未在重组方面提出或测试过。

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.