Constructing a Robust Multi-Gene Phylogeny and Studying Host and Plastid Evolution in the Alveolate Protist Dinoflagellata

[344186]鞭毛藻是一种对海洋生态系统至关重要的微生物。虽然它们是鱼类和其他动物的食物，但它们中的一些是珊瑚礁的生命支柱，其中许多会形成赤潮，从而造成环境问题。由于其生态和经济意义，了解这些生物的进化和多样化具有很高的意义。康涅狄格大学的林森杰和张欢的研究重点是利用核（核糖体DNA）和线粒体基因序列研究这些生物之间的系统发育关系，研究范围广泛的鞭毛类物种。这些基因的序列将通过基于pcr的克隆和自动测序来确定，并利用各种方法构建系统发育树来研究鞭毛动物的进化。该项目的具体目标包括：1)识别甲藻的早期分化谱系，重建甲藻的辐射模式；2)评估珊瑚礁共生生活方式在鞭毛藻进化过程中的出现时间；3)鞭毛藻如何使其营养途径多样化；4)评估有毒物种如何进化。该计划的结果将构成许多种鞭毛藻的第一个广泛的多基因组采样，并将为这一重要生物群体提供一个强大的系统发育框架。从这个项目将获得关于鞭毛藻与疟疾寄生虫疟原虫等密切相关的生物的关系的见解。此外，还有望获得对沿海环境管理和保护政策制定有价值的新信息。该项目还将通过将研究发现整合到课程中，拓宽研究生培养，丰富课程设置。特别是，这项研究的结果将帮助学生了解这些看似简单的微生物的多样性和复杂性，以及如何使用强大的分子工具来回答基本的进化问题。最后，这笔赠款将使ppi能够继续致力于鼓励少数民族和女学生参与科学研究。

0344186LinDinoflagellata are microscopic organisms that are critical to the marine ecosystem. While they are food for fish and other animals, some of them are life support of coral reefs, and many of them cause environmental problems by forming red tides. Due to the ecological and economical significance, understanding the evolution and diversification of these organisms is of high interest. Research by Senjie Lin and Huan Zhang at the University of Connecticut is focused on studying phylogenetic relationships among these organisms using nuclear (ribosomal DNA) and mitochondrial gene sequences for a wide span of dinoflagellate species. Sequences of these genes will be determined using PCR-based cloning and automated sequencing, and phylogenetic trees will be constructed using various methods to study dinoflagellate evolution. Specific objectives of this project include 1) identifying early-diverging lineages of dinoflagellates and reconstructing the radiation pattern for dinoflagellates; 2) assessing when the coral reef symbiont life-style emerged during dinoflagellate evolution; 3) studying how dinoflagellates diversified their trophic pathways; and 4) assessing how toxic species evolved. Results from this proposed project will constitute the first broadly based sampling of multiple genomes for many species of dinoflagellates and will provide a robust phylogenetic framework for this important group of organisms. Insights will be obtained from this project regarding dinoflagellate relationships with closely related organisms like the malaria parasite Plasmodium. Furthermore, novel information valuable for policy making in coastal environment management and conservation is expected. This project will also broaden graduate student training and enrich the curriculum for courses through integration of the discoveries into the curriculum. In particular, the results from this study will help students to appreciate how diverse and complex these seemingly simple microorganisms can be and how powerful molecular tools can be used in answering basic evolutionary questions. Finally, this grant will enable the PIs to continue with their commitment to encourage minority and female students to participate in scientific research.