Evolution of early development regulation using a dimorphic model

描述（由申请人提供）：本研究的重点是发现控制胚胎发生和早期幼虫发育进化变化的遗传和发育机制。通过使用具有遗传发育二态性的非模型系统，我可以直接确定单个物种早期发育和卵发生的关键机制变化。这种方法消除了传统比较方法的潜在混淆效应，并应用于受精能力卵子的遗传诊断。在这里，我建议使用发育二态性在海洋多毛藻本尼迪克特Streblospio benedicti来描述基因组差异的程度，影响卵的大小和幼虫的发育。使用定量基因组学和比较转录组学，我将确定参与调节这种发育模式决定的特定位点，并量化这些变异在母系、合子或两者中起作用的程度。具体来说，我将利用连锁作图来确定与发育和生殖性状相关的数量性状位点（qtl）。此外，我将使用卵母细胞和早期胚胎的转录组来确定这两种后代类型在基因表达的丰度和时间上的差异。这项提议的研究是第一个研究如何在单一物种中进化出关键的发育决定因素，如卵的大小。

DESCRIPTION (provided by applicant): This research focuses on the discovery of genetic and developmental mechanisms that govern evolutionary change in embryogenesis and early larval development. By using a non-model system with a heritable developmental dimorphism, I can directly ascertain key mechanistic changes in early development and oogenesis within a single species. This approach eliminates the potentially confounding effects of more traditional comparative approaches, and has applications for genetic diagnosis of fertilization competent eggs. Here I propose to use the developmental dimorphism in the marine polychaete Streblospio benedicti to characterize the extent of genomic divergence contributing to egg size and larval development. Using quantitative genomics and comparative transcriptomics, I will determine the specific loci involved in regulating this development mode determination, and quantify the extent that these variants act maternally, zygotically or both. Specifically, I will ue linkage mapping to identify quantitative trait loci (QTLs) associated with developmental and reproductive traits. In addition, I will use the transcriptomes of oocytes and early embryos to ascertain how these two offspring types differ in abundance and timing of gene expression. The proposed research is the first study to investigate how critical developmental determinants such as egg size can evolve using a single species.