Marine Biotech Fellowship: Population Genetics and Gene Flow in Hydrothemal Vent Communities

深海热液喷口由零星分布的生境系统组成 有专性的，多样的，高度专业化的无柄群落 有机体 这些地点提供了一个很有希望的研究机会 深海中的扩散和基因流动。 既往等位酶研究 这些动物中的几种显示， 遗传变异性和只有有限的遗传指标 人口之间的分离。 最令人惊讶的是， Riftia pachyptila（一种vestimentiferan管虫）的遗传研究， 表明很少或没有种群间的变化，但它一直是 建议有有限的幼虫扩散能力，而研究 Bathymodiolus thermophilus（一种喷口贻贝）的研究表明， 喷口种群之间存在着明显的遗传分离， 看起来是一个很小的，分散的幼虫 鉴于 这两个物种之间的大分类差异和低 观察到的R. pachyptila，上述 差异提供了很少的洞察人口遗传 这些独特的社区。 最需要的是 分类学上密切相关的足够的遗传变异 物种，以检测种群遗传亚结构， 同时考虑到系统发育的限制。 目前正在罗格斯大学进行的研究（NSF OCE-8917211）旨在 在评估基因流动的速度和系统的关系， 与深海热液喷口有关的软体动物种群。 双壳类贻贝和囊贻贝的等位酶研究 的喷口遗址已接近完成，线粒体DNA（mtDNA） 研究才刚刚开始。 管蠕虫Riftia的平行研究 pachyptila也在进行中。 该项目将在两个主要方面扩展这些正在进行的研究 的方式 首先，由于以前的研究发现， B等位酶多态性。thermophilus和R. pachyptila，a more 检测匿名核DNA限制性内切酶的敏感技术 将开发位点多态性以调查遗传变异。 这些数据，沿着mtDNA限制位点数据， 提供遗传变异的全面、多位点分析， 研究中心内和研究中心间（母体和双亲来源） 在这些有机体中。 其次，该项目将调查遗传 巨大的海口蛤的变异 C. magnifica有大的卵和幼虫阶段，被认为是 非营养型。 通过引入C. magnifica，这项研究将 能够对获得的结果进行直接的遗传比较 和另一只双壳贝类B一起嗜热菌，它似乎有 营养不良的幼虫和可能更大的传播能力。

Deep-sea hydrothermal vents comprise systems of patchy habitats with obligate, diverse, highly specialized communities of sessile organisms. These sites provide a promising opportunity to study dispersal and gene flow in the deep sea. Previous allozyme studies of several of these animals have revealed generally low levels of genetic variability and only limited indications of genetic separation between populations. What is most surprising is that genetic studies of Riftia pachyptila (a vestimentiferan tube worm), indicated little or no inter-population variation, but it has been suggested to have limited larval dispersal ability, whereas studies of Bathymodiolus thermophilus (a vent mussel) demonstrated significant genetic separation between vent populations in spite of what appears to be a small, broadly dispersing larva. Given the large taxonomic difference between these two species and a low level of observed genetic variation in R. pachyptila, the above discrepancy provides little insight into population-genetic processes in these unique communities. What is most needed is sufficient genetic variation in taxonomically closely related species in order to detect population genetic sub-structuring while at the same time considering phylogenetic constraints. Studies currently underway at Rutgers (NSF OCE-8917211) are aimed at assessing rates of gene flow and systematic relationships of molluscan populations associated with deep-sea hydrothermal vents. Allozyme studies of mytilid and vesicomyid bivalves from a variety of vent sites are nearly completed, and mitochondrial DNA (mtDNA) studies have just begun. Parallel studies of tube worms, Riftia pachyptila, are also underway. This project will expands upon these ongoing studies in two main ways. First, since previous studies found only a low level of allozyme polymorphism in B. thermophilus and R. pachyptila, a more sensitive technique of assaying anonymous nuclear DNA restriction- site polymorphism will be developed to survey genetic variation. These data, along with the mtDNA restriction-site data, will provide a comprehensive, multi-locus analysis of genetic variation, within and between sites (both maternally and biparentally derived) in these organisms. Second, this project will survey genetic variation in the giant vent clam, Calyptogena magnifica. C. magnifica has large eggs and a larval stage that is believed to be non-planktotrophic. By including C. magnifica, this research will be able to make direct genetic comparisons to the results obtained with another vent bivalve, B. thermophilus, which appears to have planktotrophic larvae and presumably greater dispersal abilities.