Evolution of the mRNA pool in Drosophila eggs and its effect on development

描述(申请人提供)：在包括人类在内的动物中，母亲为卵子提供驱动关键早期发育阶段的mRNAs和蛋白质。这些由母体提供的因素直接控制着早期的发育过程，并为其余的发育确立了轨迹。在实验室中，改变模式生物中母体沉积因子的水平可以对发育产生巨大影响，从而对成年表型也会产生巨大影响。尽管这些由母体提供的因素对生物体的发育和健康很重要，但人们对它们是如何进化的知之甚少。这特别令人感兴趣， 因为对这一发育阶段的基因控制必须在两个不同的基因组之间协调，母亲的基因组和受精卵的基因组，一种可能对进化构成特殊挑战的上位性。果蝇属中的苍蝇物种，其丰富的物种多样性涵盖了5000万年的分化时间，为这样的研究提供了一个很好的模型。果蝇系统的优势是拥有模式物种黑腹果蝇雌性物种沉积的mRNAs和蛋白质的广泛目录，许多研究已经在了解其中许多因子的特定发育和调节作用方面进行了大量研究。尽管之前在黑腹毛虫上做了大量工作，但我们对这些母源因子如何在不同物种间存在差异知之甚少。这项工作建议：1)利用mRNA测序方法表征果蝇种内和种间胚胎中由母亲沉积的和后来由受精卵转录的mRNA池，2)确定母体和合子mRNA池变化的系统发育模式和生活史相关性，3)确定物种内和物种间mRNA池进化更替的遗传机制。这个项目的目标是了解这些信使核糖核酸库是如何进化的，以及这些变化将对生物体的发育过程和适应性产生什么影响。

DESCRIPTION (provided by applicant): In animals, including humans, mothers supply eggs with the mRNAs and proteins that drive the critical early stages of development. These maternally supplied factors directly control early developmental processes, and establish trajectories for the rest of development. Altering the levels of maternally deposited factors in model organisms in the laboratory can have dramatic effects on development, and hence adult phenotypes. Despite the importance of these maternally supplied factors to the development and fitness of the organism, little is known about how they evolve. This is of particular interest, because genetic control over this period of development has to be coordinated across two different genomes, that of the mother and that of the zygote, a form of epistasis which may pose a particular challenge to evolution. The fly species in the genus Drosophila, with its rich diversity of species covering 50 million years of divergence time, provide a great model for such a study. The Drosophila system has the advantage of extensive catalogs of the mRNAs and proteins deposited by females of the model species D. melanogaster, and much research has gone into understanding the specific developmental and regulatory roles of many of these factors. Despite the extent of the previous work in D. melanogaster, we know very little about how these maternally derived factors vary across species. This work proposes to: 1) characterize the mRNA pools in embryos, both those deposited by the mother and those later transcribed by the zygote, within and between Drosophila species, using mRNA sequencing methods, 2) determine phylogenetic patterns and life-history correlates of maternal and zygotic mRNA pool changes, and 3) identify genetic mechanisms underlying the evolutionary turnover of mRNA pools within and between species. The goal of this project is to understand how these mRNA pools evolve, and what the effect of these changes will be on the developmental process and the fitness of the organism.