title: Shifting fitness landscapes in response to altered environments.
abstract: The role of adaptation in molecular evolution has been contentious for decades. Here, we shed light on the adaptive potential in Saccharomyces cerevisiae by presenting systematic fitness measurements for all possible point mutations in a region of Hsp90 under four environmental conditions. Under elevated salinity, we observe numerous beneficial mutations with growth advantages up to 7% relative to the wild type. All of these beneficial mutations were observed to be associated with high costs of adaptation. We thus demonstrate that an essential protein can harbor adaptive potential upon an environmental challenge, and report a remarkable fit of the data to a version of Fisher's geometric model that focuses on the fitness trade-offs between mutations in different environments.
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors.forename: Ryan T
authors.initials: RT
authors.lastname: Hietpas
authors.affiliation: School of Life Sciences, École Polytechnique Fédérale de Lausanne, Switzerland.|Swiss Institute of Bioinformatics (SIB).
authors.forename: Claudia
authors.initials: C
authors.lastname: Bank
authors.affiliation: School of Life Sciences, École Polytechnique Fédérale de Lausanne, Switzerland.|Swiss Institute of Bioinformatics (SIB).
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Jensen
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors.forename: Daniel N A
authors.initials: DNA
authors.lastname: Bolon
mesh_terms: D000222:Adaptation, Physiological / Q000235:genetics*; D004777:Environment; D019143:Evolution, Molecular; D056084:Genetic Fitness; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics; D017354:Point Mutation; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics; D012641:Selection, Genetic
chemical_list: C074510:HSP82 protein, S cerevisiae; D018841:HSP90 Heat-Shock Proteins; D029701:Saccharomyces cerevisiae Proteins
keywords: Adaptation; Fisher's geometric model; adaptive walk; distribution of fitness effects; experimental evolution