ADVANCE Fellows Award: Modularity of the Arthropod Body Plan: A Comparative Test

蚂蚁、蜘蛛和龙虾（节肢动物）都是由重复的身体部分组成的。通常每个节段都有一对肢体，这些肢体决定了不同节肢动物的生活方式：它们可以用来行走、游泳、觅食等。对像螃蟹和苍蝇这样的不同动物的比较表明，不同节肢动物群体的节段和四肢可以有很大的不同。然而，这仍然是未知的部分是否可以独立发展这种专门化。沿着身体轴的部分是自由进化的，还是一个部分的进化特化导致邻近的部分发生变化？这个问题将通过比较密切相关物种的肢体和节结构的变化，在选定的甲壳类动物群体中进行测试。根据这些数据，可以重构片段进化的演化模式，以确定片段能够独立进化的程度。这一进化分析将与甲壳类动物胚胎的一系列实验相结合，以评估片段的进化模式如何与发育过程中产生片段的机制相关联。主要的动物群体在它们的身体构造方式上是不同的，也就是说，它们表现出不同的身体计划。了解身体计划是如何组织的，为解释它们是如何进化提供了一个工具。这项工作解决了一个关于节肢动物身体结构进化的基本问题：节肢动物有模块化设计吗？然后，这项工作将明确地将进化中显示的模块化与开发中的模块化联系起来。

Ants, spiders, and lobsters (arthropods) are built from repeated parts called body segments. Typically each segment has one pair of limbs and these limbs define the lifestyles of different arthropods: they can be used for walking, swimming, feeding, etc. Comparisons of animals as different as crabs and flies, show that segments and limbs can be very differently specialized in different arthropod groups. However, it is still unknown whether segments can evolve such specializations independently. Are segments along the body axis free to evolve on their own or do evolutionary specializations of one segment cause neighboring segments to change? This question will be tested in selected groups of crustaceans by comparing changes to limb and segment structure in closely related species. From these data, the evolutionary pattern of segment evolution can be reconstructed to determine the degree to which segments can evolve independently. This evolutionary analysis will be coupled to a series of experiments on crustacean embryos to evaluate how evolutionary patterns of segmentation are linked to mechanisms that generate segments during development. The major groups of animals are distinct in the ways their bodies are built, that is, they show distinct body plans. Understanding how body plans are organized provides a tool for interpreting how they evolve. This works addresses a fundamental question about the evolution of arthropod body plans: do arthropods have a modular design? This work will then explicitly link the modularity shown in evolution to modularity in development.