CAREER: Genomic, transcriptomic, and developmental drivers of thermal adaptation among natural populations of Drosophila

University Of Vermont & State Agricultural College, Burlington VT

Investigators

Abstract

Extreme temperature can kill thermally sensitive individuals in a population and lead to the evolution of thermal tolerance, because only thermally tolerant individuals survive and reproduce under these conditions. Young individuals may be particularly vulnerable to thermal stress, but there is a gap in knowledge about how effects of thermal stress experienced early in life impact later life stages, and how such developmental constraints affect thermal adaptation. This project will uncover the genes and cellular processes that have evolved to enable natural populations of the fruit fly Drosophila melanogaster to survive and thrive across a wide range of thermal environments across the globe. This research is important because it will characterize how organisms respond to environmental change during their lifetimes and how populations respond to environmental selection over longer evolutionary time scales. The results from this project will advance the fields of ecological and evolutionary physiology. This project will have broad societal impacts through the training of the next generation of scientists from diverse socioeconomic backgrounds and through dissemination of science to the public by producing an educational video about physiological change in relation to environmental change. The objective of this project is to reveal evolved mechanisms of thermal tolerance across life stages among natural populations of Drosophila melanogaster. In oviparous animals with external embryonic development, embryos are vulnerable to changes in temperature because they are directly exposed to the external environment, have low thermal tolerance, and cannot behaviorally avoid extreme conditions. Thus, thermal selection is likely to target the embryonic life stage. Accordingly, embryos of tropical populations of D. melanogaster are more heat tolerant than embryos of temperate populations, whereas adult heat tolerance is the same across populations around the globe. Yet, it is not known how tropical embryos physiologically cope with extreme heat. To fill this gap in knowledge, the project will integrate genomic mapping, transcriptomics, protein biochemistry, and confocal fluorescence microscopy to identify the genetic and physiological bases of divergence in embryonic thermal tolerance among temperate and tropical populations. This CAREER award will integrate research and educational goals to (1) develop assessment tools of undergraduate student performance in scientific reasoning, (2) train a postdoctoral associate as a teacher-scholar, and (3) create an online science educational video on the physiology of environmental change. 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.