Systematics and Evolution of Nematode Family Rhabditidae

DEB-9981632David H.菲奇博士大卫H.纽约大学的惠誉获得了一笔研究小杆线虫科物种间进化关系的拨款。 栖息地的多样性和绝对的丰富性使小杆虫科成为一个重要的分类单元，但它是生物多样性，生殖和进化方面了解最少的动物群体之一。 最近的证据表明，一些农业上重要的寄生虫出现在小杆线虫科，提高了重要性，否则“自由生活”的线虫研究寄生虫的起源或指导搜索与寄生虫密切相关的自由生活模式。 此外，该家族还包括秀丽隐杆线虫，其作为发育遗传学模型的使用使该物种成为地球上研究最深入的动物之一。 需要一个基因组学来测试这个模型的推广，并从C.其他小杆虫科和其他后生动物系统。 此外，还需要研究雄性的形态和行为之间可能存在的相关性，例如雄性尾巴形态的进化变化和雄性交配行为之间的相关性。 这种相关性可能提供洞察可能的预适应和模式的选择导致的多样性rhabditid形式。形态和分子数据将被用来推断一个Rhabditidae的系统发育。 来自最近的发展和超微结构研究的强大的同源性标准将用于形态特征的分析，如男性交配囊（“男性尾巴”）的功能。 所有已知（和一些尚未描述的）分类群的形态数据将与著名的小杆动物学家沃尔特·苏德豪斯（柏林自由大学）合作汇编。 将收集至少两个已知在该分类学水平上具有遗传学信息的基因座的分子数据，即18 S核糖体RNA基因的几乎完整序列和RNA聚合酶II基因座的部分序列。 初步数据表明，所有三个数据分区提供一致的系统发育信息，从而允许一个“全证据”的方法来重建小杆线虫的系统发育。

DEB-9981632David H. FitchDr. David H. Fitch at New York University has been awarded a grant to study the evolutionary relationships among species in the nematode family Rhabditidae. Habitat diversity and sheer abundance alone make Rhabditidae an important taxon, yet it is one of the most poorly understood animal groups in terms of biodiversity, phylogeny and evolution. Recent evidence suggests that some agriculturally important parasites arose within Rhabditidae, elevating the importance of these otherwise "free-living" nematodes for research on the origins of parasites or directing searches for free-living models closely related to parasites. Moreover, the family includes Caenorhabditis elegans, whose use as a model in developmental genetics has made that species one of the most intensively studied animals on Earth. A phylogeny is required to test generalizations from this model and to bootstrap information on genome functionality from C. elegans to other Rhabditidae and other metazoan systems. The phylogeny will also be required to test possible correlations between form and behavior, such as those between evolutionary changes in male tail morphology and male copulatory behavior. Such correlations may to provide insight into possible preadaptations and modes of selection resulting in the diversity of rhabditid forms.Morphological and molecular data will be used to infer a phylogeny for Rhabditidae. Robust homology criteria derived from recent developmental and ultrastructural studies will be used in the analysis of morphological characters, such as features of the male copulatory bursa ("male tail"). Morphological data for all known (and some still-undescribed) taxa will be compiled in a collaboration with renowned rhabditid zoologist Walter Sudhaus (Freie Universitat Berlin). Molecular data will be collected for at least two loci known to be phylogenetically informative at this taxonomic level, nearly complete sequences of 18S ribosomal RNA genes and partial sequences from the RNA Polymerase II locus. Preliminary data suggest that all three data partitions provide congruent phylogenetic information, thus allowing a "total evidence" approach to reconstruct rhabditid phylogeny.