Building a genotype-phenotype-fitness map of adaptation is a central goal in evolutionary biology. It is difficult even when adaptive mutations are known because it is hard to enumerate which phenotypes make these mutations adaptive. We address this problem by first quantifying how the fitness of hundreds of adaptive yeast mutants responds to subtle environmental shifts. We then model the number of phenotypes these mutations collectively influence by decomposing these patterns of fitness variation. We find that a small number of inferred phenotypes can predict fitness of the adaptive mutations near their original glucose-limited evolution condition. Importantly, inferred phenotypes that matter little to fitness at or near the evolution condition can matter strongly in distant environments. This suggests that adaptive mutations are locally modular—affecting a small number of phenotypes that matter to fitness in the environment where they evolved—yet globally pleiotropic—affecting additional phenotypes that may reduce or improve fitness in new environments.
- Dmitri A Petrov
- Kerry Geiler-Samerotte
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
- Vaughn S Cooper, University of Pittsburgh, United States
- Received: July 20, 2020
- Accepted: December 2, 2020
- Accepted Manuscript published: December 2, 2020 (version 1)
© 2020, Kinsler et al.
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