Exploring the Role of Altered Hybrid Recombination in Contributing to Speciation

描述(申请人提供)：进化生物学中的一个主要问题，确定生物多样性的遗传来源，最好的答案是在物种形成的界面上检查物种，这些物种是已知杂交的密切相关的物种。最近的遗传学进展突显了杂交在这些物种中的普遍性。此外，密集标记分析表明，物种之间的遗传交换并不均匀地分布在整个基因组中。这项建议旨在了解哪些因素导致了整个基因格局中基因流动的这种区域差异。物种形成方面的许多工作都集中在了解那些造成繁殖障碍的因素上，特别是在物种间差异较大的地区。这些区域可能对应于在不同遗传背景中选择的物种形成基因，或者是限制物种间基因交换的结构变异，如染色体倒置。除了倒位，还没有鉴定出通常区分最近分化的物种的结构特征。我们的研究建议调查许多杂交分类群，并了解是什么导致了物种之间的遗传交换的差异。具体地说，我们建议通过计算来预测杂交种之间相对于物种内连锁图谱的重组率差异。然后，我们将确定杂交重组率的变化(与物种内重组率相比)是否与物种间核苷酸分歧的变化有关。我们预测，这种相关性将突出基因组中在物种形成中重要的区域。这些变化可能是由于遗传变异起到了反转的作用，阻止了杂交等位基因被整合到基因组中。因此，我们计划在我们的分类群调查中解剖这些区域，并检查这些特征是否有任何共同的遗传元素来区分最近分化的物种可能有助于这种模式。最近对人类的研究揭示了个体内和个体之间基因组结构差异的广泛证据。其中一些变异与疾病有关；然而，我们对这些变异在我们基因组结构中的作用的整体了解仍然有限。我们的研究旨在了解这些变异是否通过破坏基因交换在促进物种形成方面发挥作用，这也与疾病有关。通过利用各种生物系统中的现有数据，我们的研究结果有可能预测基因组的哪些区域可能在其他研究系统的物种形成中发挥重要作用。

DESCRIPTION (provided by applicant): A major question in evolutionary biology, determining the genetic source of biodiversity, is best answered by examining species at the interface of speciation - closely related species that are known to hybridize. Recent genetic advances have highlighted the pervasiveness of hybridization in these species. Further, dense marker analysis shows that genetic exchange between species is not uniformly distributed across the genome. This proposal aims to understand which factors contribute to this regional variation in gene flow across the genetic landscape. Much work in speciation has been focused on understanding those factors that produce barriers to reproduction, focusing particularly on regions where divergence between species is high. These regions may correspond to speciation genes that are selected against in different genetic backgrounds, or structural variants such as chromosomal inversions that limit interspecies gene exchange. Beyond inversions, no structural features have been identified which commonly differentiate recently diverged species. Our research proposes to survey many hybridizing taxa and understand what contributes to variation in genetic exchange between species. Specifically, we propose to computationally predict recombination rate differences in hybrids relative to within species linkage maps. We will then determine if changes in hybrid recombination rates (as compared to within-species recombination rates) are associated with changes in between species nucleotide divergence. We predict that this correlation will highlight regions of the genome important in speciation. These changes could be due to genetic variants that act like inversions to prevent hybrid alleles from being incorporated into the genome. Therefore, we plan to dissect these regions in our survey of taxa and examine if these feature any common genetic elements that distinguish recently diverged species could contribute to the pattern. Recent research in humans has revealed extensive evidence of genomic structural variation within and between individuals. Some of these variants have been connected to disease; however, our overall understanding of the role of these variants in contributing to the structure of our genome is still limited. Our stuy aims to understand if these variants play a role in facilitating speciation by disrupting genetic exchange, which has also been linked to disease. By making use of existing data in a variety of biological systems, the results of our research have the potential to make predictions about which regions of the genome are likely to be important in speciation in other research systems.