MOLECULAR SYSTEMATICS AND EVOLUTION OF GENUS CAULERPA

要求对具有生态和生物医学重要性的泛热带属Caulerpa进行分子系统研究。本研究的具体目标是：1)基于核糖体ITS序列、26S核糖体DNA和叶绿体编码rbcL和psbA基因四个独立的分子数据集，建立健全的蕨属植物分子系统发育；2)鉴定单系群，与目前的属分类进行比较，并表征形态和生化进化；3)比较不同物种的分子进化模式和速度；4)确定推断的系统发育假说是否与这些藻类的印度-西太平洋起源假设相一致。以及Caulerpa的系统发育模式是否与可能共享共同海洋生物地理历史的热带海洋生物的模式相关。大的单细胞植物蕨属是单细胞的例子，具有复杂的内外形态和分化的功能。该属的代表最近被认为对地中海的生物多样性构成威胁，并被认为是次生代谢物caulerpenyne毒理学研究的主题。这些藻类的系统发育视角将为这些特征的进化和表征提供见解。虽然已经提出了这些藻类的系统发育和海洋生物地理学假说，但它们尚未在具有DNA序列数据的分类群广泛采样的背景下进行测试。该项目的重点将包括评估形态、超微结构和生化特征的演变，并阐明海洋生物地理学假说（例如特提斯变异模型）下分子变异的速率和模式，以评估当今分布的历史原因。PI在温带和热带海洋藻类分类学和生态学方面有超过15年的工作经验，另外在热带海洋绿藻分子系统学方面有10年的工作经验。这个项目的成功完成将增加我们对海洋藻类系统发育、历史生物地理学和海洋生物分子进化模式的理解。

Support is requested for a molecular systematic investigation of the genus Caulerpa, a pantropical genus with ecological and biomedical importance. The specific objectives of the proposed study are to: 1) establish a robust molecular phylogeny of the Caulerpa based on four independent molecular data sets: nuclear ribosomal ITS sequences, 26S ribosomal DNA, and chloroplast encoded rbcL and psbA genes; 2) identify monophyletic groups for comparison with the current taxonomy of the genus, and characterization of morphological and biochemical evolution, 3) compare the pattern and rate of molecular evolution for different species, and 4) determine whether the inferred phylogenetic hypotheses are consistent with a presumed Indo-West Pacific origin of these algae, and if phylogenetic patterns of Caulerpa are correlated with the patterns of togther tropical marine organisms that may have shared a common marine biogeographic history. The large unicellular plants of Caulerpa are examples of single cells with a complex internal and external morphology with differentiated functions. Representatives of this genus have been recently implicated as a threat to biodiversity in the Mediterranean Sea and as the subject of toxicological studies on the secondary metabolite, caulerpenyne. A phylogenetic perspective of these algae will provide insights into the evolution and characterization of these features. Although phylogenetic and marine biogeographic hypothesis have been proposed for these algae, they have not been tested in the context of broad sampling of taxa with DNA sequence data. The focus of the project will include an evaluation of the evolution of morphological, ultrastructural and biochemical features, and elucidation of the rates and patterns of molecular variation at the with marine biogeographic hypotheses, (e.g., Tethyan vicariance models) to assess the historical causes of present day distribution. The PI has over fifteen years experience working with temperate and tropical marine algal taxonomy and ecology and another ten years working on the molecular systematics of tropical marine green algae. Successful completion of this project will increase our understanding of marine algal phylogeny, historical biogeography, and the rates of patterns of molecular evolution in marine organisms.