Functional evolution of segmentation gene regulatory networks in insects

描述（由申请人提供）：Evo-Devo领域的一个核心问题是控制胚胎发育的基因如何在进化过程中发生变化。在昆虫中，虽然基本的分段身体计划是高度保守的，但我们的研究和其他研究揭示了在不同昆虫谱系中控制这一过程的基因的意想不到的变化。本研究将基于节肢动物系统发育的建立和对模式昆虫黑腹果蝇（Drosophila melanogaster）分节功能的深入了解，采用比较的方法探讨昆虫中促进分节的机制的多样性。我们将通过胚胎调控基因的获得和丢失以及它们之间相互作用的变化来研究调控回路的重新布线是如何在进化过程中发生的。我们将在实验室建立非模式昆虫系统的基础上，开展不同昆虫类群的功能研究，以验证以下假设：(1)对规则分割基因网络在昆虫中是高度动态的；(2)在进化过程中，控制片段形成的基因与上游基因之间的调控相互作用被重新连接；(3)基分枝昆虫的分节需要非规范的类对规则基因。这些研究将有助于我们了解调控胚胎发育的基本机制以及这些机制在昆虫辐射过程中如何发生变化。这种方法的新颖之处在于，它系统地比较了数亿年前分化的物种之间单一生物过程（分割）的调节机制。本项目将培养分子生物学、遗传学和分子进化方向的博士后1名，研究生4名，本科生至少3名。

DESCRIPTION (provided by applicant): A central question in the field of Evo-Devo is how genes controlling embryonic development change during evolution. In insects, although the basic segmented body plan is highly conserved, our studies and others have revealed unexpected variation in the genes that control this process in different insect lineages. Here we will utilize comparative approaches, based on established arthropod phylogeny and the in-depth understanding of segmentation in the model insect Drosophila melanogaster, to explore the diversity of mechanisms promoting segmentation in insects. We will examine how re-wiring of regulatory circuits has occurred during evolution through the gain and loss of embryonic regulatory genes and changes in the interactions among them. We will build upon the establishment of non-model insect systems in our lab to carry out functional studies in diverse insect taxa to test the hypotheses that: (1) The pair-rule segmentation gene network is highly dynamic in insects; (2) Regulatory interactions between genes specifying segment formation and the upstream genes controlling them have been re-wired during evolution; and (3) Non-canonical pair-rule-like genes are required for segmentation in basally branching insects. These studies will contribute to our understanding of fundamental mechanisms regulating embryonic development and how these mechanisms have changed during the radiation of insects. This approach is novel in its systematic comparison of the regulatory mechanisms underlying a single biological process - segmentation - across species that diverged hundreds of millions of years ago. This project will train one postdoctoral fellow, four graduate students and at least three undergraduate students in molecular biology, genetics and molecular evolution.