DISSERTATION RESEARCH: Mechanisms of adaptation to saltwater by an amphibian

该项目将调查一些美洲绿树蛙（Hyla cinerea）种群耐受高盐浓度的遗传和细胞过程，以及盐水如何影响两栖动物的自然历史。栖息地质量和数量的持续下降增加了了解生物如何适应新的或不断变化的环境的紧迫性。进化可能会迅速发生，足以拯救种群，保护物种在面对不断变化的环境（包括世界各地淡水湿地日益盐碱化）时免于灭绝。随着湿地盐分的增加，许多淡水湿地生物，如鱼、海龟和青蛙可能会在当地灭绝。然而，在咸淡湿地中发现了美洲绿树蛙的种群。该项目将比较沿海和内陆种群的青蛙在基因表达、卵孵化、幼虫发育以及其他特征方面的差异。这些结果将有助于更好地理解适应盐水环境的过程。此外，该项目还将吸引K-12学生，特别是那些在科学领域代表性不足的群体的学生。为了确定假定的耐盐蛙种群是否因盐暴露而与淡水种群发生适应性分化，本研究采用了一种常见的花园因子设计，研究了无尾两栖动物发育的三个阶段（卵、幼虫和变态后）的多个生物组织水平的终点。该研究将描述盐水暴露后的转录组反应，并将这些模式与随后的蛋白质表达和适应性相关（例如，发育率、存活率）联系起来。在此过程中，该项目将整个生物体水平上发生的选择压力与构成适应基础的分子过程联系起来。该项目将确定盐耐受性的机制，并区分关于遗传变异和适应性变化进化中可塑性作用的相互竞争的假设。

This project will investigate the genetic and cellular processes that allow some populations of the American green tree frog (Hyla cinerea) to tolerate high salt concentrations, and how saltwater affects the natural history of amphibians. The ongoing decline of habitat quality and quantity has increased the urgency to understand how organisms adapt to new or changing environments. Evolution might occur rapidly and quickly enough to rescue populations and protect species from being lost in the face of a changing environment, including by the increasing salinization of freshwater wetlands around the world. As wetlands grow saltier, many freshwater wetland organisms such as fish, turtles, and frogs may become locally extinct. However, populations of the American green tree frog have been discovered in brackish wetlands. This project will compare frogs from coastal and inland populations for differences in gene expression, egg hatching, and larval development, among other traits. The results will lead to a much better understanding of the process of adaptation to saline environments. In addition, the project will engage with K-12 students, especially those from groups that are underrepresented in the sciences.To determine whether putatively salt-tolerant frog populations are adaptively diverging from freshwater populations in response to salt exposure, this study uses a common garden, factorial design to investigate endpoints across multiple levels of biological organization across three stages of anuran amphibian development (egg, larval, and post metamorphosis). The study will characterize transcriptomic responses following saltwater exposure and relate these patterns to subsequent protein expression and fitness correlates (e.g., developmental rates, survival). In doing so, the project links selective pressures occurring at the level of the whole organism to the molecular processes that underlie adaptation. The project will identify the mechanisms that underlie salt tolerance and differentiate between competing hypotheses about the role of genetic variation and plasticity in the evolution of adaptive change.