Collaborative Research: Diversity and Biogeography of Marine Oligotrich and Choreotrich Ciliates Assessed by Morphological and Molecular Markers

合作研究：通过形态和分子标记评估海洋寡毛纤毛虫和群毛纤毛虫的多样性和生物地理学

• 批准号: 0221137
• 负责人: George McManus
• 金额: $ 20.75万
• 依托单位: University of Connecticut
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-15 至 2006-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0221137&HistoricalAwards=false
• 关键词: Collaborative; Research; Diversity; Biogeography; Marine

Microzooplankton assemblages in the sea are often dominated by oligotrich and choretrich ciliates. Ciliate communities are diverse and dynamic, with rapid changes in abundance and species composition over short time scales. Understanding the nature and implications of diversity in ciliate communities is critical if we are to extrapolate measurements (e.g. grazing, growth) obtained with one ciliate community or a few species in culture to regional or global models of food webs. In addition, the degree of inter- and intraspecific genetic variability across spatial and temporal scales is unknown for these ciliates. Finally, analysis of morphological markers alone has generated considerable debate between researchers who argue that all ciliates are cosmopolitan versus those who believe that there is limited gene flow between geographically isolated ciliate populations. One key to addressing all of these issues is to quantify the correspondence between molecular markers and morphology within and between populations. At present, however, molecular data are sparse for these ecologically important groups. This project combines molecular and morphological methods to elucidate the diversity of marine ciliates in the subclasses Choreotrichia and Oligotrichia (Cl: Spirotrichea). This large group of planktonic grazers comprises an important trophic link between phytoplankton and bacterial production and higher consumers. The main focus of the study is to collect DNA sequence data from natural populations of choreotrichs and oligotrichs, and to relate these sequences to morphospecies determined by traditional methods. A combination of techniques will be applied to handpicked cells from natural assemblages to evaluate diversity across a range of scales from meters to thousands of kilometers, with intensive sampling of ciliates along the southern coast of New England and the western coast of the United Kingdom. Intraspecific genetic variability will also be quantified as changes within populations over short temporal and spatial scales. The study has two objectives: 1) to quantify diversity within a subset of marine oligotrich and choreotrich species sampled from nearshore environments using both morphology and molecular markers, and 2) to assess patterns of intraspecific variation on short spatial and temporal scales in a few abundant species of oligotrich and choreotrich ciliates. For both objectives, individual cells will be picked for genetic analysis and preserved for species identification. For objective one, small subunit ribosomal gene sequences will be compared. For the second objective, more variable markers will be analyzed, including the internally transcribed spacer regions (ITS1 and ITS2) of the ribosomal genes and an intervening sequence between histones H3 and H4 (H3H4IS). Combining molecular and morphological approaches, this study will produce comprehensive data on genetic diversity of populations of oligotrichs and choreotrichs. These data are an essential first step for connecting information on individual species abundances sampled across time and space to whole communities of ciliates. In addition, this work will provide the first test using molecular data on marine ciliate endemism and will train graduate students in relevant morphological and molecular techniques. The resulting data will have broader implications for questions regarding global protist diversity and biogeography and will be necessary to fully explore the role of ciliates in energy flow and nutrient cycling in marine systems.

海洋中的Microzooplankton组合通常由寡纤维纤维纤维纤维组合。 纤毛群落是多种多样的，动态的，在短时间内，丰度和物种组成的快速变化。 如果我们要推断用一个纤毛群落或几种文化中的几种物种对食品网的区域或全球模型中获得的种类，那么了解纤毛社区多样性的性质和含义至关重要。 此外，这些纤毛范围未知，空间和时间尺度之间的种内和种内遗传变异程度是未知的。 最后，仅对形态标记物的分析引起了研究人员之间的巨大争论，他们认为所有纤毛都是国际化的，而那些认为地理隔离的纤毛种群之间的基因流量有限。 解决所有这些问题的一个关键是量化人群内部和人群之间的分子标记和形态之间的对应关系。 然而，目前，对于这些生态重要的群体而言，分子数据稀疏。 该项目结合了分子和形态学方法，以阐明亚类纤毛纤毛的多样性和寡素（Cl：spirotrichea）。这大批浮游放牧者包括浮游植物与细菌生产与更高消费者之间的重要营养联系。 该研究的主要重点是从浮游和寡聚体的天然种群中收集DNA序列数据，并将这些序列与由传统方法确定的形态物种联系起来。 从天然组合的精心挑选的细胞将使用多种技术，以评估从米到数千公里的一系列尺度上的多样性，并在新英格兰南部海岸和英国西部海岸进行了大量的需要次采样。 种内遗传变异性也将被量化，因为在短时和空间尺度上人群中的变化。 这项研究有两个目标：1）在使用形态和分子标记物中从近海环境中采样的海洋寡头和choreotrich物种中的多样性，以及2）评估在短的空间和时间尺度上的种内变化模式，这些模式在几种寡素和吉他上的几种丰富物种中。 对于这两个目标，都将选择单个细胞进行遗传分析并保存用于物种鉴定。 对于物镜，将比较小的亚基核糖体基因序列。 对于第二个目标，将分析更多可变标记，包括核糖体基因的内部转录间隔区（IS1和IS2）以及组蛋白H3和H4（H3H4IS）之间的中间顺序。 结合了分子和形态学方法，这项研究将为寡头和杜鹃花种群的遗传多样性提供全面的数据。 这些数据是将跨时间和空间采样的单个物种丰度与整个纤毛群落联系起来的重要第一步。此外，这项工作将使用有关海洋纤毛典写的分子数据提供首次测试，并将培训研究生采用相关的形态和分子技术。 最终的数据将对有关全球原生物多样性和生物地理学的问题具有更广泛的影响，并且对于充分探索纤毛在能量流和养分循环中的作用是必要的。