Developmental Mechanisms of Body Plan Evolution

身体计划进化的发育机制

• 批准号: 9724003
• 负责人: Rudolf Raff
• 金额: $ 17万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-01 至 2000-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9724003&HistoricalAwards=false
• 关键词: Developmental; Mechanisms; Body; Plan; Evolution

Raff 9724003 Although there are several million species of animals, they fall into groups representing 35 basic body plans (phyla). The phyla appeared in the Cambrian radiation, and have existed for over a half billion years. The study of the evolution of development has revealed two important and unexpected observations. The first is that radically different developmental modes can evolve rapidly among closely related taxa. The second is that master regulatory genes are highly conserved, even among morphologically widely disparate phyla. These results suggest that developmental reorganization has occurred largely by co-option of existing genes and pathways, and that we can exploit the expression of conserved regulatory genes to determine how body plan transformations took place. This study investigates the evolution of the pentameral body plan of echinoderms with the bilaterally symmetric body plan of their sister group, the chordates. This proposal focuses on the transformations that have converted a bilaterally symmetric body plan into a pentameral one, and on finding shared processes that govern axial determination in disparate phyla. The proposed work will seek to establish a potential echinoderm homolog to the notochord in the induction of axial structures. The hypothesis that such a homolog exists can be confirmed by defining patterns of expression of echinoderm homologs of vertebrate axial determination genes. The project will exploit a sea urchin species that develops directly into a juvenile adult in only four days. Genes involved in specification of vertebrate anterior-posterior and dorsal-ventral axis induction pathways will be isolated from that sea urchin. The project will characterize spatial expression patterns of the genes to infer echinoderm homologs to vertebrate axial features. The function of axial determination genes will be tested by over/ectopic expression experiments. Finally, the project will determine the role of induction processes in axial determination in echin oderms by experimental embryology and use of gene markers. This testing of inductive processes will further test the potential homologies of developmental processes in two morphologically distinct but related phyla. The results of this project will provide an insight into the evolutionary modifications of developmental processes, and into the role of developmental processes in constraining the course of morphological evolution.

拉夫9724003 虽然有几百万种动物，但它们属于代表35个基本身体计划（门）的群体。该门出现在寒武纪辐射，并已存在超过5亿年。对发展演变的研究揭示了两个重要和意想不到的观察结果。第一，在密切相关的类群中，完全不同的发育模式可以迅速进化。第二，即使在形态上差异很大的门中，主调控基因也是高度保守的。这些结果表明，发育重组主要是通过现有基因和途径的共同选择发生的，我们可以利用保守的调控基因的表达来确定身体计划的转变是如何发生的。摘要本研究探讨棘皮动物的五分体型与其姊妹群脊索动物的两侧对称体型的演化。这个建议的重点是转换双边对称的身体计划到一个五分之一，并在寻找共同的过程中，管理轴的决定在不同的门。拟议的工作将寻求建立一个潜在的棘皮动物同源物的脊索轴结构的诱导。这种同源物存在的假设可以通过定义脊椎动物轴向决定基因的棘皮动物同源物的表达模式来证实。 该项目将利用一种海胆物种，它在短短四天内直接发育成一个青少年。将从该海胆中分离出涉及脊椎动物前后轴和背腹轴诱导途径的基因。该项目将描述基因的空间表达模式，以推断棘皮动物同源脊椎动物的轴特征。轴向决定基因的功能将通过过度/异位表达实验进行测试。最后，该项目将通过实验胚胎学和基因标记的使用来确定诱导过程在棘皮动物中轴决定中的作用。这种诱导过程的测试将进一步测试两个形态上不同但相关的门的发育过程的潜在同源性。 这个项目的结果将提供一个深入了解的发展过程中的进化修改，并到发展过程中的作用，约束形态进化的过程。