Dissertation Research: Dispersal, Evolution, and Phylogeny of Membranipora (Bryozoa: Cheilostomata)

9423868在海洋等开放系统中，人们对生物的哈维尔扩散和种群间的基因流动知之甚少，因为许多海洋种群的生活史包括长距离分散阶段。这与陆地和淡水生物不同，因为它们在栖息地往往存在明显的物理不连续性，以解释种群的遗传结构，并从更长远的角度解释异地物种形成或来自地理上孤立的种群的新物种的起源。该项目将以海洋苔藓虫属Membripora(苔藓虫门：Cheilostomata)和膜毛苔藓虫种为重点，研究洋流是否是构建基因流的主要因素。分子遗传学方法(主要是线粒体DNA测序和一小部分蛋白质电泳法)将用于研究种群间基因流动的模式和速度。此外，将使用mtDNA序列数据构建膜孔菌属物种之间的系统发育或关系图，并在地理背景下进行解释，以解决关于膜孔菌属物种形成原因的假说。这项研究通过研究苔藓虫类中的一个属，将有助于我们对海洋生物多样性的了解。这些是最常见的在他们的植物一样的分枝群体中，但小的幼虫分散阶段对于种群之间的基因流动非常重要。该项目将调查一个物种内当前的基因流动模式，并通过确定该属物种之间的关系并检查它们的地理分布来开始解决地质历史上的基因流动问题。

9423868 Harvell Dispersal of organisms and gene flow among populations are poorly understood in open systems like the ocean where the life history of many marine groups includes long distance dispersing stages. This is in contrast to terrestrial and fresh water organisms with their often obvious physical discontinuities in habitat to explain genetic structure of populations and, with a more long-term view, allopatric speciation or the origin of new species from geographically isolated populations. This project will focus on the marine bryozoan genus Membranipora (Bryozoa: Cheilostomata) and the species M. membranacea to investigate whether ocean currents are a major factor in structuring gene flow. Molecular genetic methods (primarily mitochondrial DNA sequencing with a small component of protein electrophoresis) will be used to investigate patterns and rates of gene flow among populations. In addition, a phylogeny or diagram of relationships among species in the genus Membranipora will be constructed using mtDNA sequence data and interpreted in a geographic context to address hypotheses about the causes of speciation in the genus Membranipora. %%% This study will contribute to our knowledge of marine biodiversity by studying a genus in the group of organisms known as Bryozoa. These are most commonly seen in their plant-like branching colonies but the small larval dispersing phase is very important to gene flow among populations. The project will investigate current gene flow patterns within one species and begin to address geologically historical gene flow by determining relationships among species in the genus and examining their geographic distributions.