The Role of Oogenesis in Speciation

项目摘要 地球上所有的生物多样性都是通过物种形成过程产生的。虽然物种形成研究的重点是 关于物种之间生殖障碍的起源，这项工作的结果将为研究 不孕症是一个重要的生殖健康问题。虽然配子发生是一个合乎逻辑的发育过程 关于生殖隔离的研究，几乎所有的研究都集中在雄性配子发生上，很少甚至没有 研究卵子发生这项拟议中的研究假设，环境压力加速了 通过其对卵子发生的影响，遗传分歧，绘制生殖和 环境卫生。例如，环境压力已被证明会导致复发性自发性 堕胎，使这项工作与公共卫生有关。环境压力有四个主要结果， 卵子发生-转座因子、结构变异、减数分裂重组率和基因调控- 对物种形成的研究很重要。通过增加遗传差异，卵子发生 促进不同暴露的物种之间的物种形成。该提案主要侧重于 重组，同时朝着整合其他成果迈出重要一步。先前的研究 表明重组率比核苷酸分歧进化得更快。再加上有证据表明 重组率是环境敏感的，这表明环境可能是一个主要的驱动因素， 通过重组来适应当地环境。该提议利用了实验操作的便利性， 果蝇研究卵子发生的环境敏感性之间的联系，积累新的遗传 变异和随后的物种分化。首先，物种内的卵子发生将与杂种进行比较 在控制和强制降解条件下研究基因表达、染色质构象、生物体 应激反应和重组的测量。通过靶向分子途径， 转座因子沉默和DNA修复，这项工作可以间接告知这些新的积累 遗传变异，回答了进化生物学中的一个关键问题， 物种变异第二，由于杂种卵子发生的差异可能归因于生殖 不相容性影响健身，这项工作将调查健身和重组之间的关系 塑性直接与三个独特的实验应力处理。突变标记将用于比较 重组，借助一种新的高通量表型机器人。野生型股票已知是 对选定的紧张性刺激敏感或耐受的人将成为目标。这项工作的一大创新将是调查 有机体的压力反应直接比较健身治疗。从这两个地方收集的数据 在更广泛地研究复合率可塑性的机制时，这些问题将是至关重要的， 即使在这一领域进行了世纪的研究之后，它仍然是一个谜。五年内，拟开展的工作将回答 这是物种形成中的关键问题，同时也填补了卵子发生在物种形成中的重要性的主要空白。

Project Summary All biodiversity on earth is generated through the process of speciation. While speciation research is focused on the origins of reproductive barriers between species, the results of this work will inform the study of infertility, an important reproductive health concern. Though gametogenesis is a logical developmental process to study in regard to reproductive isolation, nearly all research focuses on male gametogenesis, with little to no work on oogenesis. The proposed research hypothesizes that environmental stress hastens the accumulation of genetic divergence through its impact on oogenesis, drawing connections between reproductive and environmental health. For example, environmental stress has been shown to cause recurrent spontaneous abortion, making this work relevant to public health. There are four key outcomes of environmental stress on oogenesis – transposable elements, structural variants, meiotic recombination rates, and gene regulation – that have been shown to be important to the study of speciation. By increasing genetic differences, oogenesis facilitates speciation between species that are differentially exposed. This proposal focuses primarily on recombination, while taking an important step towards integrating other outcomes. Previous research has shown that recombination rates evolve more rapidly than nucleotide divergence. This coupled with evidence that recombination rates are environmentally sensitive, suggests that the environment could be a major driver of local adaptation through recombination. This proposal leverages the ease of experimental manipulation in fruit flies to study the link between environmental sensitivity of oogenesis, the accumulation of novel genetic variation, and subsequent species divergence. First, within species oogenesis will be compared to hybrids under control and stress conditions investigating gene expression, chromatin conformation, organismal measures of stress response, and recombination. By targeting molecular pathways associated with transposable element silencing and DNA repair, this work can indirectly inform the accumulation of these novel genetic variants, answering a key question in evolutionary biology regarding sources of intra- and inter- species variation. Second, because differences in hybrid oogenesis could be attributed to reproductive incompatibilities impacting fitness, this work will investigate the relationship between fitness and recombination plasticity directly with three unique experimental stress treatments. Mutant markers will be used to compare recombination, with the aid of a novel high-throughput phenotyping robot. Wild type stocks known to be either sensitive or tolerant to selected stressors will be targeted. A major innovation of this work will be to investigate organismal stress response directly to compare fitness across treatments. The data collected from these two questions will be critical in the broader investigation of mechanisms of recombination rate plasticity, which remains a mystery even after a century of research in this area. In five years, the proposed work will answer crucial questions in speciation, while also filling a major gap of the importance of oogenesis in speciation.