Does habitat specialization drive population genetic structure of oceanic zooplankton?

这项研究将测试栖息地深度专业化是否是一个主要特征驱动大规模的种群遗传结构在开放的海洋浮游动物物种。对海洋浮游动物种群的连通性知之甚少。虽然浮游动物长期以来被认为是高基因流系统，种群间几乎没有遗传分化，但最近的观察对这一观点提出了挑战。事实上，浮游动物物种可以在宏观地理，区域，甚至更小的空间尺度上进行遗传细分。最近的研究还表明，微妙的，物种特异性的生态因素在控制浮游生物种群之间的基因流中发挥着重要作用。研究人员假设，与深度相关的栖息地，包括昼夜垂直迁移（DVM）行为，通过与海洋环流和水深的相互作用，在控制浮游生物在海洋区域之间的扩散方面发挥着关键作用。本研究将比较八种利用不同深度相关生境的浮游桡足类的种群遗传结构，以测试基于生物体深度与海洋环境相互作用的遗传结构的关键预测。本研究的目标是：1）开发新的核标记，可用于解析桡足类种群之间的遗传结构和估计基因流，2）使用多位点方法表征大西洋，太平洋和印度洋不同海洋区域8个目标物种种群之间的基因流空间格局，（3）检验中心假设，即与深度有关的生境将显著影响跨洋盆地和洋盆内的遗传结构的范围、种群间基因流动的幅度和方向以及物种内重大纵切事件的时间。利用PI最近开发的基因组资源（cDNA文库），将为每个物种开发五个（或更多）多态性核标记。将使用这些新的标记，与线粒体基因细胞色素氧化酶I相结合，在其全球分布的每一个物种的人口遗传结构的特点，使用图论和合并分析技术。将在一个结合模型（IMa）下估计种群之间的基因流动和主要分裂事件的时间，并将使用图论一致性检验评估种群结构中与深度有关的趋势假设的经验支持。由于目标物种的深度专业化和昼夜垂直迁移行为代表了不同的浮游动物物种群，因此本研究的结果将对理解和预测这些重要的浮游生态系统食草动物的遗传结构产生广泛的影响。更广泛的影响将包括指导两名研究生和多达六名本科生，为三名高中理科教师提供研究培训（请求可再生能源基金提供支助），广泛传播研究成果，通过更好地了解全球海洋主要次级生产者的遗传结构为社会作出贡献。在过去的一年里，来自代表性不足群体的四名学生参与了这项研究，其中包括一名目前从事核标记开发的硕士生。PI将继续为代表性不足的学生提供研究培训，包括夏威夷土著人和太平洋岛民。三名高中科学教师将在夏季（RET）在实验室进行研究，并将与PI合作开发新的科学课程计划和海洋科学和海洋生物多样性教学实验室。

This research will test whether habitat depth specialization is a primary trait driving large-scale population genetic structure in open ocean zooplankton species. Very little is known about population connectivity in marine zooplankton. Although zooplankton were long thought to be high-gene-flow systems with little genetic differentiation among populations, recent observations have challenged this view. In fact, zooplankton species may be genetically subdivided at macrogeographic, regional, or even smaller spatial scales. Recent studies also indicate that subtle, species-specific ecological factors play an important role in controlling gene flow among plankton populations. The investigator hypothesizes that depth-related habitat, including diel vertical migration (DVM) behavior, plays a critical role in controlling dispersal of plankton among ocean regions, through interactions with ocean circulation and bathymetry. This study will compare the population genetic structures of eight planktonic copepods that utilize different depth-related habitats, in order to test key predictions of genetic structure based on the interaction of organismal depth with the oceanographic environment. The objectives of the research are to 1) Develop novel nuclear markers that can be used to resolve genetic structure and estimate gene flow among copepod populations, 2) Characterize the spatial patterns of gene flow among populations in distinct ocean regions of the Atlantic, Pacific, and Indian Oceans for eight target species using a multilocus approach, and 3) Test the central hypothesis that depth-related habitat will significantly impact the extent of genetic structure both across and within ocean basins, the magnitude and direction of gene flow among populations, and in the timing of major slitting events within species. Drawing on genomic resources (cDNA libraries) recently developed by the PI, five (or more) polymorphic nuclear markers will be developed for each species. These new markers will be used, in combination with the mitochondrial gene cytochrome oxidase I, to characterize the population genetic structure of each species throughout its global distribution using graph theoretic and coalescent analytical techniques. Gene flow among populations and the timing of major splitting events will be estimated under a coalescent model (IMa), and empirical support for the hypothesis of depth-related trends in population structure will be assessed using graph theoretic congruence tests. Because the depth specialization and diel vertical migration behaviors of the target species are representative of distinct zooplankton species groups, the results of this study will have broad implications for understanding and predicting the genetic structure of these important grazers in pelagic ecosystems.Broader impacts will include mentoring two graduate students and up to six undergraduate students, research training for three high school science teachers (RET support requested), broad dissemination of research results, and contributions to society through better understanding of the genetic structure of the dominant secondary producers of the global ocean. Four students from underrepresented groups have been engaged in the research in the past year, including one Masters student currently working on nuclear marker development. The PI will continue to provide research training for underrepresented students, including native Hawaiians and Pacific Islanders, though this research program. Three high school science teachers will conduct research in the laboratory during summers (RET), and will collaborate with the PI on development of new science lesson plans and teaching laboratories on ocean science and marine biodiversity.