DISSERTATION RESEARCH: Investigating patterns and processes of evolution, ecology, and diversification in carangiform fishes

该项目研究了两种标志性海洋鱼类--巨鳍和蓝鳍金枪鱼的遗传多样性。这两个物种都是印度洋和太平洋珊瑚礁和岩礁上的顶级捕食者，对手工渔业、商业渔业和休闲渔业都有很高的价值。这项研究将调查印度-太平洋地区遗传多样性与环境变量(例如海洋温度和洋流)之间的相关性，以确定可能导致这些鱼在不同地理位置的基因组差异的物理障碍。该项目的重点是西印度洋，该地区缺乏足够的海洋保护措施，这在很大程度上是因为缺乏为各国政府制定管理决策提供信息所需的数据。鉴于缺乏关于这两种海燕的数据，再加上它们的经济重要性，该项目具有直接的社会影响。研究人员将与政府和非营利性合作者共享数据，并纳入针对研究生的强大科学培训内容，以及与美国、南非和塞舌尔的公众接触。为了完成项目目标，研究人员将首先使用下一代测序技术进行海景遗传分析，特别是针对单核苷酸多态(SNPs)的双酶切限制性位点相关DNA测序(RADseq)，以检查它们范围内的光肩星天牛和黑猩猩个体之间的精细遗传结构。将使用将海洋学数据与这些物种的生物属性相结合的生物-物理耦合模型来分析海景属性。将建立模型，最大限度地利用与遗传数据相辅相成的空间尺度上的海洋信息。第二部分包括系统地理分析，重点是通过使用古气候数据来描述可能驱动进化并影响这两个物种历史和现在数据分布的物理和生物力量，从而描述历史上基因流动的模式。该方法使用高分辨率的古海洋模型，结合当代基于地理信息系统的物种分布建模算法，生成每个物种的古分布适宜值。这些古分布可作为对照SNP数据集进行检验的替代假设。这些分析结合在一起，将提供对影响这两个重要渔业物种多样化和连通性的当代和历史进程的洞察。

This project examines genetic diversity in two species of iconic marine fishes, the Giant Trevally and the Bluefin Trevally. Both species are top predators on coral and rocky reefs throughout the Indian and Pacific Oceans and are highly valued for artisanal, commercial, and sport fisheries. The research will investigate the correlation between genetic diversity and environmental variables (e.g., ocean temperature and currents) in the Indo-Pacific to identify physical barriers that might lead to observed differences in the genomes of these fishes in different geographic locations. The project focuses on the western Indian Ocean, a region lacking sufficient marine conservation measures in large part due to a scarcity of data necessary to inform governments making management decisions. Given the lack of data on these two species of Trevally, coupled with their economic importance, this project has direct societal implications. The researchers will share data with governmental and non-profit collaborators and incorporate strong scientific training components for graduate students, as well as engagement with members of the public in the USA, South Africa, and Seychelles. To accomplish the project objectives, the researchers will first conduct seascape genetic analyses using next generation sequencing techniques, specifically double digest restriction site associated DNA sequencing (RADseq) targeting single nucleotide polymorphisms (SNPs) to examine fine-scale genetic structure within and among C. ignobilis and C. melampygus individuals across their range. Seascape properties will be analyzed using coupled biological-physical models that integrate oceanographic data with biological attributes of these species. Models will be generated that maximize the availability of oceanographic information at a spatial scale complementary to the genetic data. The second component includes a phylogeographic analysis focused on characterizing patterns of historic gene flow by using paleoclimatic data to characterize physical and biological forces that may have driven evolution and influenced historical and present data distributions of the two species. This methodology uses high-resolution paleoceanographic models coupled with contemporary GIS-based species distribution modeling algorithms to generate paleodistribution suitability values for each species. These paleodistributions serve as alternate hypotheses to test against the SNP dataset. In combination, these analyses will provide insight on contemporary and historical processes shaping the diversification and connectivity of these two important fishery species.