Exploring Evolutionary History and Climate Adaptation in a Freeze-tolerant VertebrateSkelly, David

Abstract

As we consider the future of species in a changing climate, it is critical that evolutionary perspectives become part of the grounding for conservation planning. Responses to changing climate will undoubtedly vary among species, and for ectotherms, temperature plays a crucial part in many aspects of their biology such as reproduction, growth, and overwintering. Adaptation may be critical for species surviving the effects of climate change, and understanding the evolutionary history for species is an essential baseline for uncovering their adaptive potential and predicting their evolutionary trajectory. My research focuses on the wood frog (Rana sylvatica=Lithobates sylvaticus) – a cold adapted, freeze-tolerant amphibian that is simultaneously the most widely distributed amphibian in North America, and highly vulnerable to human modifications to its environment. In this dissertation, I disentangle how lineage diversification within wood frogs proceeded following the Last Glacial Maximum (LGM). I investigate how wood frog genomes adapted to environmental conditions experienced over a 32-year period and identify regions of the genome as candidates for environmental adaptation. Lastly, I perform a freeze-thaw experiment to uncover the gene-expression profile of the complex and quick freeze-thaw process, and identify candidate genes for their role in freeze- tolerance adaptation.