PRF/J: Molecular Systematics of the Sipuncula

本项目将分析一种虹膜虫的相对基因序列，推导出该物种细胞色素氧化酶（CO） I - III亚基的全部序列，并对部分CO I - III序列进行分析。这些数据将允许创建一个Sipuncula相对于其他密切相关的真鳗原生动物门的分子系统发育，其中序列数据目前可用。将根据相对基因顺序和CO I - III序列数据推导出单独的系统发育，并将检查这些系统发育是否一致，作为两种方法的检验。来自至少五个其他物种的部分序列数据将与原始序列数据进行分析，以创建该门六个所描述的科的系统发育。利用这些信息，将有可能产生一个独立的基于形态学的系统发育分析的测试。星形虫是一种分布广泛的类群，在遗传学和系统发育上很少为人所知和了解。虽然不是一个很大的门，但这种有限的多样性并没有促进对群体本身进化的理解，也没有促进基于表型（形态和个体发生）特征的门与后生动物进化的关系。从这项研究中获得的基因顺序和序列数据将对描述整个群体中线粒体基因组的细粒度和粗粒度进化至关重要。这些信息将揭示Sipuncula内的系统发育及其与后生动物的亲缘关系，并将为进一步研究广泛分布的物种和海洋分散的幼虫生物的生物地理学和种群变异提供基线遗传信息。上述所有内容都很重要，因为海洋物种在系统分类学和生物多样性研究中代表性不足。

During this project the relative gene order of a sipunculan will be analyzed, the entire sequence of cytochrome oxidase (CO) subunits I - III for this species will be derived, and same will be done for partial CO I - III sequences. These data will permit the creation of a molecular phylogeny of the Sipuncula relative to other closely related eucoelomate protostome phyla for which sequence data are presently available. Separate phylogenies will be derived based on relative gene order and CO I - III sequence data, and those will be checked for congruence as a test of the two methods. Partial sequence data from at least five other sipunculan species will be analyzed with the original sequence data in order to create a phylogeny of the six described families of the phylum. Using this information it will be possible to produce an independent test of a phylogenetic analysis based solely on morphology. %%% The Sipuncula is a widely distributed group that is little known and poorly understood genetically and phylogenetically. Though not a large phylum, this limited diversity hasn't facilitated understanding of either the evolution of the group itself or the relationship of the phylum to metazoan evolution based upon phenotypic (morphological and ontogenetic) characters. The gene order and sequence data that will result from this study will be essential for characterizing fine- and coarse-grained evolution of the mitochondrial genome within the entire group. Such information will reveal answers about phylogeny within the Sipuncula and affinities with the Metazoa, and will also provide baseline genetic information for further studies concerning the biogeography of widespread species and population variation of ocean-dispersed larval organisms. All of the foregoing is important because marine species are under-represented in studies of systematics and biodiversity.