Insights into the Evolution of Chordate Body Plans Through Correlated Developmental Genetic and Fate Mapping Studies of the Early Embryos of Amphioxus

通过文昌鱼早期胚胎的相关发育遗传和命运图谱研究洞察脊索动物身体计划的进化

• 批准号: 0078599
• 负责人: Nicholas Holland
• 金额: $ 33万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-01 至 2004-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0078599&HistoricalAwards=false
• 关键词: Insights; into; Evolution; Chordate; Body

0078599HollandAmphioxus is a lower chordate that represents the closest living invertebrate relative of the vertebrates. In recent years, gene expression data from relatively late developmental stages of amphioxus have helped to indicate body part homologies between amphioxus and vertebrates. For instance, mapping the expression of neural genes has suggested that amphioxus (and, by extension, the proximate ancestor of the vertebrates) has major brain regions homologous to those of vertebrates. In contrast, relatively little is yet known about gene expression during early development of amphioxus. In the vertebrates, such early acting genes play key roles in setting up signaling centers (organizers), establishing primary body axes, and large-scale patterning of the tissues. This proposal is focused on genes involved in the initial establishment and early regionalization of the amphioxus central nervous system. The ultimate aim is to test the hypothesis that mechanisms for establishing and large-scale patterning of the nervous system were already largely in place in the last common ancestor of amphioxus and the vertebrates. The research comprises two tightly linked approaches. The first is to isolate and study the expression of amphioxus homologs of vertebrate genes known to be important in early nervous system development. The second is to use vital dye tracing to elucidate cell and tissue movements associated with the early morphogenesis of the amphioxus nervous system, including gastrulation, extension of the anterior-posterior axis of the embryo, and establishment of regional identities. Taken together, the expression of key developmental genes in the context of a detailed map of cell and tissue movements will provide insights into the evolution of mechanisms involved in the establishment and regionalization of the central nervous system during the early evolution of the vertebrates.

0078599荷兰文昌鱼是一种低等脊索动物，是脊椎动物中最接近的无脊椎动物。 近年来，文昌鱼相对较晚发育阶段的基因表达数据有助于表明文昌鱼和脊椎动物之间的身体部位同源性。 例如，绘制神经基因的表达图表明，文昌鱼（以及脊椎动物的近缘祖先）的主要脑区与脊椎动物的脑区同源。 相反，文昌鱼早期发育过程中的基因表达却知之甚少。 在脊椎动物中，这些早期作用基因在建立信号中心（组织者），建立初级身体轴和组织的大规模图案中起着关键作用。 本研究的重点是文昌鱼中枢神经系统的初步建立和早期区域化的基因。 最终的目的是检验这样一个假设，即神经系统的建立和大规模模式化的机制在文昌鱼和脊椎动物的最后一个共同祖先中已经基本到位。 这项研究包括两个紧密相连的方法。 第一个是分离和研究文昌鱼同源脊椎动物基因的表达，这些基因在早期神经系统发育中很重要。 第二个是使用活体染料示踪来阐明与文昌鱼神经系统的早期形态发生相关的细胞和组织运动，包括原肠胚形成、胚胎前后轴的延伸以及区域身份的建立。 两者合计，在细胞和组织运动的详细地图的背景下的关键发育基因的表达将提供深入了解在脊椎动物的早期进化过程中的中枢神经系统的建立和区域化的机制的演变。