Testing for repeated evolution in a radiation of alpine beetles

How repeatable is evolution? Can genetic variation in ancestors repeatedly give rise to new species adapting in parallel to environmental challenges? Studying a highly diverse group of North American ground beetles, the researchers will explore the hypothesis that natural selection acted on the same molecular pathways when species adapted to alpine environments during past glacial-interglacial climate cycles. Additionally, comparative analysis of recently diverged alpine beetle species will shed light on the process of climate-based adaptation, which can improve our understanding of the risks and possible evolutionary outcomes of rapid contemporary climate change. The specific molecular pathways involved in environmental adaptation are highly relevant to ongoing efforts to mitigate the effects of climate change in conservation management, pest management, and even human health. This project will broaden participation and active learning opportunities through mentoring of high school student interns through the Wisconsin Youth Apprenticeship Program, as well as undergraduate and graduate students from underrepresented backgrounds through programs at the University of Wisconsin-Madison. These mentees will receive training in genetics, physiology, data science, and science communication. Alpine environments exhibit strong environmental gradients that are expected to exert selection pressure on stress tolerance traits, including temperature tolerance, desiccation resistance, and hypoxia tolerance. Through comparative genomic statistical analyses of 50 closely related beetle species (Coleoptera: Carabidae: Nebria (Catonebria)), the researchers will test for repeated evolution in protein-coding and non-coding regions, genome structural variation, and gene families. In addition, they will test for repeated gene regulatory evolution in abiotic stress pathways through stress tolerance experiments, using multiple sister-species pairs that vary in their ecology (riparian versus alpine habitat specialists). This combination of analyses will test whether there is genomic evidence for repeated evolution in ground beetles adapted to alpine environments and identify the specific genetic mechanisms that enable these species to survive environmental stress. The results will also identify broadly relevant functional genomic data that can advance comparative research on ecologically important traits in the tree of life. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.