Collaborative Research: Developmental, Molecular, and Evolutionary Analysis of Chaetognaths:a Deuterostome-Like Ecdysozoan.

0236565马丁代尔毛颚类动物，或称“箭蠕虫”，是世界上所有海洋中发现的最丰富的海洋无脊椎动物之一。 这种动物普遍存在的系统发育位置目前尚不清楚。 直到最近，毛颚类被认为是基于其放射状卵裂程序，经典的肠腔，囊胚孔的后部位置和三部分成年人的身体计划等发育特征的基础后口动物。 新的分子证据，包括Hox基因的数据，在这一建议中提出的，已经表明，毛颚类不是后口动物，但与蜕皮动物，如节肢动物和线虫密切相关的基原口动物。 事实上，毛颚类现在被认为是后生动物中最关键和最未被充分研究的类群之一，可以深入了解原口类身体计划的进化。然而，只有少数的毛颚发育的细胞和分子研究。 Martindale和Halanych博士的建议描述了一套全面的多学科方法，旨在描述毛颚类胚胎如何“工作”。利用现代发育（细胞内细胞谱系标记和激光细胞缺失实验）和分子（克隆，原位杂交）技术，Martindale和Halanych将收集这些有趣动物正常发育的重要信息，并能够研究后生动物遗传调控机制的保护。 此外，基因发现技术（EST筛选）将提供有价值的身体计划进化的祖先机制的新信息。这些数据将不仅是重要的，以确定毛颚类的系统发育位置，但也提供了分子和发育的见解蜕皮动物的进化分支，和“evolveability”的发展计划。 毛颚类可能是最具信息性和最易处理的基础无脊椎动物系统，可以让我们了解线虫和节肢动物分支的进化，这是地球上两种遗传学研究最多的动物。

0236565MartindaleThe chaetognaths, or "arrow worms", are one of the most abundant marine invertebrates found in all the world's seas. The phylogenetic position of this ubiquitous group of animals is currently unknown. Until recently, chaetognaths were considered to be basal deuterostomes based on developmental features such as their radial cleavage program, classic enterocoeley, posterior position of the blastopore, and tripartite adult body plan. New molecular evidence, including Hox gene data presented in this proposal, has suggested that chaetognaths are not deuterostomes but basal protostomes closely allied with ecdysozoans such as arthropods and nematodes. In fact, chaetognaths are now thought to be one of the most pivotal and understudied groups of metazoan animals for gaining insight into the evolution of protostome body plans. Only a handful of cellular and molecular investigations of chaetognath development have ever been made, however. Drs. Martindale and Halanych's proposal describes a comprehensive and multidisciplinary set of approaches designed to characterize how chaetognath embryos "work". Using both modern developmental (intracellular cell lineage labeling and laser cell deletion experiments) and molecular (cloning, in situ hybridization) techniques, Martindale and Halanych will collect vital information on the normal development of these interesting animals, and be able to and examine the conservation of genetic regulatory mechanisms in the Metazoa. In addition, techniques of gene discovery (EST screening) will provide valuable new information on the ancestral mechanisms of body plan evolution. These data will not only be important to determine the phylogenetic position of chaetognaths, but to also provide molecular and developmental insight in to the evolution of the ecdysozoan clade, and the "evolveability" of developmental programs. Chaetognaths could be the most informative and tractable basal invertebrate system available that will allow an understanding of the evolution of the nematode and arthropod clades, the two most genetically heavily studied group of animals on earth.