Evolution of early development regulation using a dimorphic model

描述(申请人提供)：这项研究的重点是发现控制胚胎发生和早期幼虫发育的进化变化的遗传和发育机制。通过使用具有可遗传发育二型性的非模型系统，我可以直接确定在单个物种的早期发育和卵子发生中的关键机制变化。这种方法消除了更传统的比较方法的潜在混淆效果，并应用于受精能力卵子的遗传诊断。在这里，我建议使用海洋多毛类Streblospio benedicti的发育二型性来表征有助于卵子大小和幼体发育的基因组分歧的程度。利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基因座，并量化这些变异在多大程度上发挥母性、合子或两者兼而有之的作用。具体地说，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基因座(QTL)。此外，我将使用卵母细胞和早期胚胎的转录本来确定这两种后代类型在丰度和基因表达时间上的差异。这项拟议的研究是第一次研究卵子大小等关键发育决定因素是如何使用单一物种进化的。

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.