MOLECULAR EVOLUTION OF MARINE PROTISTS

在自由生活和寄生的群体中的进化模式 单细胞原生生物在种群、物种和 一般水平。 现代分子和形态测量方法很少 被应用于这些形式，因此，他们的模式， 进化是无法准确推断的。 少量的现代 现有的数据表明进化模式的模型 从对更高的多细胞形式的研究中推断， 适用于单细胞形式。 现代自然科学研究进展 种群和物种的原生生物一直缓慢，由于缺乏 适当的"模式生物"， 实验室可以集中。 海洋硅藻，中肋骨条藻， 提出作为研究自由生活光合作用的模型系统， 有色植物谱系中的原生生物。 过去在这方面开展的工作 实验室已经确定，这种生物的种群是 在分子水平上的遗传差异， 高等植物，但在形态上没有显着差异 水平 叶绿体DNA（cpDNA）的分化模式是 目前正在审查中。 这是首次对cpDNA进行定量研究 任何原生生物种群水平的变异。 本研究是 目前正在扩展到核基因，包括基因和间隔区， rDNA顺反子区域和单拷贝核序列。 引物PCR也被用于开发新的探针。 的 从分子水平推断的遗传多样性模式的一致性 差异正在与获得的细胞形态模式进行比较， 从扫描电子显微镜照片分析形态测定， 计算机集成数字成像系统。 这项工作的相关性 生物体被用作模型 在分子水平上研究原生生物种群遗传学的系统， 许多研究结果具有广泛的适用性。 学生参与 所有阶段的工作，并密切监督直接由PI。

The patterns of evolution in groups of free-living and parasitic unicellular protists are poorly understood at the population, species and generic levels. Modern molecular and morphometric methods have rarely been applied to these forms, and consequently, their patterns of evolution cannot be inferred with accuracy. The small amount of modern data that do exist indicate that models of the patterns of evolution inferred from research on higher multicellular forms probably cannot be applied to unicellular forms. The progress of modern research on natural populations and species of protists has been slow due to the lack of appropriate "model organisms" on which research efforts from different labs can be focused. The marine diatom, Skeletonema costatum, is proposed as a model system for the study of free-living photosynthetic protists in the chromophyte lineage. Past work conducted in this laboratory has already established that populations of this organism are as genetically different at the molecular level as different genera of higher plants, but are not significantly different at the morphological level. Patterns of differentiation in chloroplast DNA (cpDNA) are currently being examined. This is the first quantitative study of cpDNA variation at the population level in any protist. This research is currently being extended to nuclear genes, including genes and spacer regions in the rDNA cistron and a single-copy nuclear sequence. Arbitrarily primed PCR is also being used to develop new probes. The concordance of the patterns of genetic diversity inferred from molecular differences are being compared to patterns of cell morphology obtained from scanning electron micrographs analyzed morphometrically by a computer-integrated digital imaging system. The relevance of this work to biomedical research is that the organism is being used as a model system to study protist population genetics at the molecular level and many of the findings have broad applicability. Students are involved in all phases of the work and are closely supervised directly by the P.I.