An Integrative Analysis of Gene Conversion

减数分裂是为受精做准备的基因组还原分裂，是有性生殖生物生命周期的关键阶段。 在减数分裂期间，同源染色体相互作用，通过同源染色体之间的相互交换（交叉，CO）或基因转换（GC），导致DNA的可遗传重排。 在大多数真核生物中，这些事件确保适当的染色体分离、促进 DNA 修复并为遗传多样性提供基础。 已经提出了描述重组机制的详细模型，并且可以使用GC事件的频率和分布的测量来测试这些模型的准确性。 减数分裂重组还会导致连锁不平衡（LD）的破坏，即连锁位点处等位基因组的非随机关联，在进化过程中群体遗传学家利用它来更好地了解物种、其表型和基因组如何进化。 最近的模型表明，在某些基因组区域中，GC 在分解 LD 方面可能与 CO 一样重要。 该项目的近期目标是测量两种不同生物体（植物拟南芥和后生动物黑腹果蝇）多个位点的 GC 频率。 研究人员还将对相同位点的重组进行群体遗传估计，并将这些估计值与 GC 和 CO 的直接测量进行比较，以完善重组的群体遗传模型及其对全基因组 LD 模式的影响。 该项目的长期目标是了解减数分裂重组如何在多细胞生物体中运作以及它如何影响基因组变异和进化。除了加深我们对经典遗传问题——基因转换的理解外，该提案还通过建立真正的跨学科学院伙伴关系、为代表性不足群体的初级科学家的参与创建平台以及以第一手研究和合作的形式强调研究生水平教育来产生更广泛的影响。

Meiosis, the reductive division of the genome in preparation for fertilization, is a critical phase in the life-cycle of sexually reproducing organisms. During meiosis homologous chromosomes interact resulting in the heritable rearrangement of DNA, through reciprocal exchange between homologous chromosomes (crossing over, CO) or gene conversion (GC). In most eukaryotes these events ensure proper chromosome segregation, facilitate DNA repair and provide a basis for genetic diversity. Detailed models describing recombination mechanisms have been proposed and measurements of the frequency, and distribution of GC events can be used to test the accuracy of these models. Meiotic recombination also causes the breakdown linkage disequilibrium (LD), the non-random association of sets of alleles at linked loci, over evolutionary time which population geneticists use to better understand how species, their phenotypes, and their genomes evolve. Recent models suggest that GC may be as important as CO in breaking down LD in some genomic regions. The immediate goals of this project are to measure GC frequency at multiple loci in two distinct organisms, the plant Arabidopsis thaliana and the metazoan Drosophila melanogaster. The investigators will also make population genetic estimates of recombination at the same loci and compare these estimates with direct measurements of GC and CO in order to refine population genetic models of recombination and its effect on genome wide patterns of LD. The long-term goal of the project is to understand how meiotic recombination operates in multi-cellular organisms and how it influences genome variation and evolution. In addition to deepening our understanding of a classic genetic problem - gene conversion - this proposal also provides broader impact by building truly interdisciplinary collegial partnerships, creating a platform for participation by junior scientists from underrepresented groups and emphasizing graduate level education in the form of first-hand research and collaboration.