PRF/J: Molecular Systematics of the Sipuncula

在这个项目中，将分析一种吸虫的相关基因序列，推导出该物种的细胞色素氧化酶(CO)亚基I-III的完整序列，并对CO I-III的部分序列进行同样的分析。这些数据将有助于建立Sipuncula的分子系统学，相对于目前已有序列数据的其他密切相关的Eucoelomate原生动物门。将根据相对基因序列和CO I-III序列数据得出不同的系统发育图，并将检查这些数据的一致性，作为两种方法的测试。我们将用原始序列数据分析至少另外五个吸虫物种的部分序列数据，以创建该门所描述的六个科的系统发育图。利用这些信息，将有可能对仅基于形态的系统发育分析进行独立的测试。Sipuncula是一个分布广泛的类群，在遗传学和系统发育上鲜为人知，也鲜为人知。虽然不是一个大的门，但这种有限的多样性既不利于理解该类群本身的进化，也不利于理解该门与基于表型(形态和个体发育)特征的后生动物进化的关系。这项研究将产生的基因顺序和序列数据将对描述整个群体内线粒体基因组的细粒度和粗粒度进化至关重要。这些信息将揭示关于Sipuncula内的系统发育和与后生动物的亲缘关系的答案，还将为进一步研究广布物种的生物地理学和海洋散布的幼虫生物的种群变异提供基线遗传信息。所有上述内容都很重要，因为海洋物种在系统学和生物多样性研究中的代表性不足。

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.