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驱动公海浮游动物物种大规模种群遗传结构的主要特征。人们对海洋浮游动物种群的连通性知之甚少。尽管浮游动物长期以来被认为是高基因流动系统，种群之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、物种特有的生态因素在控制浮游生物种群之间的基因流动方面发挥着重要作用。研究人员假设，与深度相关的栖息地，包括海底垂直迁移(DVM)行为，通过与海洋环流和水深测量的相互作用，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。这项研究将比较利用不同深度相关生境的八种浮游桡足类的种群遗传结构，以检验基于生物深度与海洋环境相互作用的遗传结构的关键预测。这项研究的目标是：1)开发新的核标记，用于解析遗传结构和估计桡足类种群之间的基因流动；2)使用多位点方法描述大西洋、太平洋和印度洋不同海洋区域8个目标物种种群间基因流动的空间格局；3)检验与深度有关的生境将显著影响海洋盆地和海洋盆地内遗传结构的程度、种群间基因流动的大小和方向以及物种内主要切割事件的时间这一中心假设。利用国际植物研究所最近开发的基因组资源(cDNA文库)，将为每个物种开发5个(或更多)多态核标记。这些新的标记将与线粒体基因细胞色素氧化酶I结合使用，利用图论和联合分析技术来表征每个物种在全球分布过程中的种群遗传结构。种群间的基因流动和主要分裂事件的时间将在合并模型(IMA)下估计，并将使用图论一致性检验来评估对种群结构深度相关趋势假说的经验支持。由于目标物种的深度专门化和垂直迁徙行为代表了不同的浮游动物种群，本研究的结果将对理解和预测这些远洋生态系统中这些重要的食草动物的遗传结构具有广泛的意义。广泛的影响将包括指导两名研究生和最多六名本科生，对三名高中科学教师的研究培训(要求RET支持)，广泛传播研究成果，以及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做出贡献。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工作的硕士学生。国际学生联合会将继续为代表不足的学生提供研究培训，包括夏威夷原住民和太平洋岛民，尽管这一研究计划。三名高中科学教师将在实验室进行夏季研究(RET)，并将与PI合作制定关于海洋科学和海洋生物多样性的新科学教案和教学实验室。

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.