Will natural populations adapt in the face of climate change? In a rapidly changing world, there is an urgent need to know the conditions necessary for adaptation. In the past, unrelated populations or species independently adapted in similar ways to increased temperatures. The goal of this research is to use such natural experimental replicates to identify ecological, physiological and genetic predictors of adaptation. For animals or plants, it is technically difficult to discover the precise genetic mechanism encoding new traits. This research focuses instead on many wild populations of yeast and includes the model organism for genetics, Saccharomyces cerevisiae, which humans also use to ferment food and beverages. Yeast are exceptionally tractable in the laboratory, and there are wild forest populations of even domesticated species with population biology that is surprisingly similar to that of animals. Work on this project will provide an interdisciplinary training that is in high demand by integrating field, laboratory and bioinformatic approaches. It will train undergraduate and graduate students, including students from underrepresented groups in science. Researchers will also test whether the same principles of natural yeast thermal adaptation also governed adaptation of wild yeast to local human-associated environments. Families, elementary school children and others in the community will learn about the concepts and findings of the research through local events and school visits.
Populations that show convergent evolution provide natural replicates for understanding the ecological, phenotypic and molecular basis of adaptation. The research team's overall objective is to identify the mutations and evolutionary processes that characterize convergent evolution in the wild, using thermal adaptation in yeast as the study system. The research will test for convergent thermal evolution within species and across phylogenetic scales by sampling many yeast populations from four woodland species, including Saccharomyces cerevisiae. Population genomic analyses will distinguish new adaptive mutations from standing genetic variation or gene flow. The power of wild yeast genetics can show the underlying mechanisms of adaptation to an extent that would be almost impossible in any other system. The experiments involve analyses to infer phylogenetic relationships for detecting convergence and evolutionary context; field sampling and physiological screens identifying thermal adaptation in natural yeast populations; the identification of mutations underlying convergent thermal adaptation, their verification using transgenic allele swaps; and integrated analyses predicting species ranges and climate change response by generating correlative and mechanistic models that include mutation availability, phenotypic plasticity, population size and growth.
This grant was cofunded by the Integrative Ecological Physiology Program in the Division of Integrative Organismal Systems, the Evolutionary Processes Cluster in the Division of Environmental Biology, and The Rules of Life in the Division of Emerging Frontiers in Directorate for Biological Science.
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.
