Defining the genetic and cellular basis of morphological diversity in Drosophila

项目总结 这项提议的总体目标是确定改变复杂三维结构的基因变异。 并确定这些基因如何对细胞数量、形状和行为产生影响 在开发过程中。在形态发生中起重要作用的发育基因以复合体形式连接在一起 然而，我们目前还不知道如何在基因调控的背景下对变体进行优先排序 网络。因此，我将在基因调控网络层面上进行一项进化案例研究，以 确定有助于物种间形态多样化的基因类型，并表征 它们对单个细胞的影响。为了实现这个目标，我需要一个系统，其中基因调控网络 潜在的数量性状是众所周知的，其中关键的变异可以在分辨率 个体基因。果蝇分支的后叶特别适合于 将遗传变异与形态发生结果联系起来。最近的工作已经确定了许多组件 控制后叶发育的基因调控网络，包括构图分子(转录 因子和信号分子)和细胞效应物(细胞骨架调节因子)。此外，它们之间的杂交 所有这三个物种都是存活的，并显示出中间叶的形态，这允许严格绘制 导致它们表型截然不同的基因组区域。在目标1中，我将映射序列 负责后叶形态的数量变异。我将在物种中使用RNA-seq 杂交以确定包含表达变异的基因，期望这些基因中的一些 有助于后叶的形态多样性。然后，我将使用 基于CRISPR的互补性检验。在《目标2》中，我将确定构图分子和细胞 效应器影响单个细胞的数量、形状和行为。我会用细胞标记和成像 测量来自突变体、不同物种和不同物种的后叶的细胞数量、大小和行为 物种混血儿。通过完成这项提议，我将把基因调控网络中的变异与 决定细胞大小和形状的分子机制，这将使后叶发育成为首要因素 形态发育和进化的系统级研究系统。

PROJECT SUMMARY The overall goal of this proposal is to determine the genetic variants that alter complex three-dimensional morphologies and to determine how these genes exert their influence on cell number, shape and behavior during development. Developmental genes that are important in morphogenesis are linked in complex hierarchies, yet we do not currently know how to prioritize variants within the context of a gene regulatory network. I will therefore undertake an evolutionary case study at the level of a gene regulatory network to determine the types of genes that contribute to morphological diversification between species and characterize their effects on individual cells. To accomplish this goal, I require a system where the gene regulatory network underlying a quantitative trait is well-understood, and where critical variants can be mapped at the resolution of individual genes. The posterior lobe in the Drosophila melanogaster clade is particularly well-suited to connecting genetic variation to morphogenetic outcomes. Recent work has identified many components of the gene regulatory network controlling posterior lobe development, including patterning molecules (transcription factors and signaling molecules) and cellular effectors (cytoskeletal regulators). Furthermore, hybrids between all three species are viable and exhibit intermediate lobe morphologies, which allows for rigorous mapping of genomic regions contributing to their drastically different phenotypes. In Aim 1, I will map sequences responsible for quantitative variation in posterior lobe morphology. I will use RNA-seq in species and hybrids to identify genes containing expression variation, with the expectation that some of these genes contribute to morphological diversity in the posterior lobe. I will then validate strong candidates using a CRISPR-based complementation test. In Aim 2, I will determine how patterning molecules and cellular effectors influence the number, shape and behavior of individual cells. I will use cell labeling and imaging to measure cell number, size and behavior in posterior lobes derived from mutants, different species and species hybrids. By completing this proposal, I will connect variation in the gene regulatory network to molecular mechanisms that dictate cell size and shape, which will develop the posterior lobe as a premier system for systems-level studies of morphological development and evolution.