EAPSI: Evolution and Biogeography of an East Asian-North American Distribution in Sedges, a Hyper-Diverse Group of Flowering Plants

莎草(莎草属：苔草属)是开花植物的五大属之一，也是温带地区种类最多的植物属。莎草估计有2100个物种，是研究更广泛的生物多样性和进化模式问题的理想类群，因为1)该属物种的高度多样性，2)由微生境专门化驱动的物种形成，以及3)物理扩散能力的限制。在该属中，一支约60种的分支分布于北美和欧亚大陆，分布于北美和欧亚大陆，在美国东部和日本有两个生物多样性中心。该项目将利用分子系统学和生物地理学方法的组合来重建这些莎草的进化关系，并模拟它们的地理范围随时间的变化。该奖项将允许这位研究人员前往日本对东亚莎草进行采样，包括狭义分布的日本特有植物。实验室工作将产生DNA序列，这些DNA序列将与北美莎草首席研究员之前产生的数据相结合。这是与冈山科学大学植物系统学家兼莎草专家星野拓治博士合作的研究项目。在日本的研究期间，将从收集的二氧化硅干燥的叶子样本中提取DNA。6个DNA序列区域将被靶向并通过聚合酶链式反应进行扩增。生成的DNA序列将用Sequencher编辑，然后手动比对并与程序Muscle进行比对。Beast是一个用于系统发育分析的贝叶斯程序，它将被用来重建组合的特征系统学，并通过用化石数据校准节点年龄来执行分歧测年。这项研究将检验这样一种假设，即该分支曾经广泛存在于北半球的一片连续的森林中，而今天的多样性模式是由于最近北美东部和日本的物种辐射。这项工作将研究Beringia在形成当今植物区系多样性格局中所起的作用，并研究由于气候和环境变化而导致的扩散受限植物区系的长期范围变化。该奖项由东亚和太平洋暑期学院项目资助一名美国研究生的暑期研究，由NSF和日本科学促进会共同资助。

Sedges (genus: Carex) are one of the five largest genera of flowering plants, and the most diverse plant genus in the temperate zone. Sedges, with an estimated 2100 species, are an ideal group for examining questions about broader patterns of biodiversity and evolution due to 1) high species diversity in the genus, 2) speciation driven by microhabitat specialization, and 3) restricted ability for physical dispersal. Within this genus, a clade of about 60 species in sections Laxiflorae, Paniceae, Limosae, and Bicolores are distributed widely across North America and Eurasia, with two centers of biodiversity in the eastern United States and Japan. The project will utilize a combination of molecular systematics and biogeographic methods to reconstruct the evolutionary relationships of these sedges and model their geographic range shifts through time. The award will allow the researcher to travel to Japan to sample East Asian sedges, including narrowly distributed Japanese endemics. Laboratory work will produce DNA sequences that integrate with data previously generated by the principal investigator for North American sedges. This is a collaborative research project with Dr. Takuji Hoshino, a plant systematist and sedge expert at the Okayama University of Science. During the research in Japan, DNA will be extracted from the collected silica-dried leaf samples. Six DNA sequence regions will be targeted and amplified by PCR. The generated DNA sequences will be edited with Sequencher, then aligned manually and with the program MUSCLE. BEAST, a Bayesian program for phylogenetic analyses, will be used to reconstruct a combined character phylogeny and perform divergence dating by calibrating node ages with fossil data. The research will test the hypothesis that the clade was once widespread throughout a continuous forest in the Northern Hemisphere, and that the present-day patterns of diversity are due to recent species radiations in both eastern North America and Japan. This work will investigate role that Beringia played in shaping patterns of diversity in the present-day flora, and examine long-term range shifts in dispersal-limited flora due to changes in climate and environment. This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the Japan Society for the Promotion of Science.