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

描述（由申请人提供）：在包括人类在内的动物中，母亲为卵子提供驱动发育关键早期阶段的mRNA和蛋白质。这些由母体提供的因素直接控制早期发育过程，并为其余的发育建立轨迹。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，从而对成体表型产生巨大影响。尽管这些由母体提供的因子对生物体的发育和适应性很重要，但人们对它们是如何进化的却知之甚少。这一点特别令人感兴趣， 因为在这一发育阶段的遗传控制必须在两个不同的基因组之间进行协调，即母亲的基因组和受精卵的基因组，这是一种上位性的形式，可能对进化提出特别的挑战。 果蝇属中的蝇类，其丰富的物种多样性覆盖了5000万年的分歧时间，为这样的研究提供了一个很好的模型。果蝇系统的优势在于模式物种D的雌性所沉积的mRNA和蛋白质的广泛目录。许多研究已经深入了解了许多这些因素的特定发育和调节作用。尽管在D.黑腹鱼，我们对这些母体衍生的因子在不同物种之间的差异知之甚少。这项工作的目的是：1）使用mRNA测序方法表征果蝇属物种内和物种间胚胎中的mRNA库，包括由母体沉积的mRNA库和随后由合子转录的mRNA库，2）确定母体和合子mRNA库变化的系统发育模式和生活史相关性，以及3）鉴定物种内和物种间mRNA库进化周转的遗传机制。该项目的目标是了解这些mRNA库如何演变，以及这些变化对生物体的发育过程和适应性的影响。

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.