Dissertation Research: Comparative Anatomy and Morphogenesis in the Cephalobinae (Nematoda:Rhabditida)

滨江的加州大学的詹姆斯·鲍德温博士和丹尼尔·邦巴格先生获得了一笔赠款，用于研究一组微生物摄食线虫--头蜱亚科的细胞外摄食附属物的结构和进化。该项目将描述这些结构的超微结构解剖，分类负责其组装的过程，并探索与理解异时性和新颖性进化相关的发育特征进化模式。由于这些结构在亚微米空间尺度上非常复杂，因此将利用电子断层扫描（一种三维电子显微镜方法）的独特应用来描述解剖结构。这些结构的形态发生将用更传统的光学显微镜进行研究。比较工作，主要是基于扫描电子显微照片的成人和青少年的形态，将与分子系统发育labor.It预计，该项目将提供一个基础上，问分类，发育和进化的问题，广泛的兴趣合作。该项目将有助于专题工作已经在进行中，通过提供强有力的假设的字符同源性，重新定义分类分组的方式，反映系统发育关系。这项研究代表了电子断层扫描的新应用，可能被证明对评估其他小型无脊椎动物的同源性有用。线虫是理解发育进化的极好模型，特别是在必须理解基因型和表型变化之间的联系的情况下。前部形态的复杂性和多样性的模式表明存在可以相对独立地彼此进化的发育模块。许多突变在这些喂养附属物可能是可行的，这将有助于识别发育调控基因负责进化的变化。

A grant has been awarded to Dr. James Baldwin and Mr. Daniel Bumbarger at University of California, Riverside to study the structure and evolution of extracellular feeding appendages in the Cephalobinae, a group of microbial feeding nematodes. The project will describe the ultrastructural anatomy of these structures, classify processes responsible for their assembly and explore patterns in developmental character evolution that are relevant to understanding heterochrony and the evolution of novelty. As these structures are extremely complex on a sub-micrometer spatial scale, a unique application of electron tomography, a three dimensional electron microscopy method, will be utilized to describe the anatomy. Morphogenesis of these structures will be studied with more traditional light microscopy. Comparative work, based primarily on scanning electron micrographs of adult and juvenile morphologies, will be done in collaboration with a molecular phylogenetic lab.It is expected that this project will provide a foundation upon which to ask taxonomic, developmental and evolutionary questions of broad interest. This project will contribute to monographic work already in progress by providing strong hypotheses of character homology with which to re-define taxonomic groupings in a manner that reflects phylogenetic relationships. The proposed research represents novel application of electron tomography that may prove useful for assessing homology in other groups of small invertebrates. Nematodes make excellent models for understanding the evolution of development, particularly where a link between genotypic and phenotypic changes must be understood. Patterns in the complexity and diversity of anterior morphology suggest the presence of developmental modules that could evolve relatively independently from one another. Many mutations in these feeding appendages will likely be viable, which will facilitate identification of developmental regulatory genes responsible for evolutionary changes.