REU: Ribosomal Genes and Chlorophyte Phylogeny

通过比较分子来显示进化关系的强大新工具将用于研究淡水和海洋绿藻，包括那些被认为与陆地植物关系最密切的绿藻。核糖核酸（RNA）分子与细胞质核糖体的比较将为一个多世纪以来一直是研究焦点的问题提供一个新的、令人兴奋的视角。其他现代方法，如电子显微镜，已经对绿藻的分类进行了重大修改，这些修改现在可以通过分子分析进行测试。绿藻细胞质核糖体RNA分子的比较也将为绿藻叶绿体分子进化的类似研究提供重要的比较依据，这种进化可能不同于细胞质核糖体RNA的进化。此外，这项研究将成为其他主要藻类研究的模型和平行研究，包括红藻和褐藻，硅藻和鞭毛藻。在这个项目中，部分18s和26s核糖体RNA分子将直接测序（通过双脱氧核苷酸引物扩展）。大量的数据集将被存储、排列、比较，并通过各种计算机程序进行分析。对这些数据进行枝系分析将为推断绿藻的古谱系和分化模式提供依据。生成的“家谱”将与基于形态学、超微结构和生化特征的家谱进行对比。核糖体RNA数据的计算机辅助枝系分析结合非分子信息将提供不同类型信息的重要综合，因此，应该有助于我们开发绿藻的自然分类系统和更好地了解陆生植物的藻类起源。

The powerful new tool of comparing molecules to show evolutionary relationships will be used in studying freshwater and marine green algae, including those green algae thought to be most closely related to the land plants. A comparison of the ribonucleic acid (RNA) molecules from cytoplasmic ribosomes will offer a new and exciting perspective on questions that have been the focus of research attention for more than a century. Other modern approaches, such as electron microscopy, have provided major revisions of the classification of green algae, revisions that can now be tested by molecular analysis. The comparison of cytoplasmic ribosomal RNA molecules of green algae also will provide a major basis for comparison to similar studies of the molecular evolution of the chloroplasts of green algae, an evolution that may be different from that of the cytoplasmic ribosomal RNAs. Also, this study will be a model for and parallel to studies of other major groups of algae including red and brown algae, the diatoms, and the dinoflagellates. In this project portions of the 18s and 26s ribosomal RNA molecules will be sequenced directly (by dideoxynucleotide primer extension). The massive data set will be stored, aligned, compared, and analyzed with various computer programs. Cladistic analysis of the data will provide the basis for inferring the ancient lineages and patterns of divergences for the green algae. The "family trees" produced will be contrasted with those based on morphological, ultrastructural, and biochemical characters. Computer-assisted cladistic analysis of ribosomal RNA data in combination with non-molecular information will provide an important synthesis of different types of information and thus, should help us develop a natural system of classification for the green algae and a better understanding of the algal origins of land plants.