title: Environment determines evolutionary trajectory in a constrained phenotypic space.
abstract: Constraints on phenotypic variation limit the capacity of organisms to adapt to the multiple selection pressures encountered in natural environments. To better understand evolutionary dynamics in this context, we selectEscherichia colifor faster migration through a porous environment, a process which depends on both motility and growth. We find that a trade-off between swimming speed and growth rate constrains the evolution of faster migration. Evolving faster migration in rich medium results in slow growth and fast swimming, while evolution in minimal medium results in fast growth and slow swimming. In each condition parallel genomic evolution drives adaptation through different mutations. We show that the trade-off is mediated by antagonistic pleiotropy through mutations that affect negative regulation. A model of the evolutionary process shows that the genetic capacity of an organism to vary traits can qualitatively depend on its environment, which in turn alters its evolutionary trajectory.
authors.affiliation: Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, United States.|Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States.
authors.forename: David T
authors.identifier: 0000-0002-8668-3476
authors.initials: DT
authors.lastname: Fraebel
authors.affiliation: Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, United States.|Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States.
authors.forename: Harry
authors.initials: H
authors.lastname: Mickalide
authors.affiliation: Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, United States.|Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States.
authors.forename: Diane
authors.initials: D
authors.lastname: Schnitkey
authors.affiliation: Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, United States.|Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States.
authors.forename: Jason
authors.initials: J
authors.lastname: Merritt
authors.affiliation: Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, United States.|Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States.|Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, United States.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Kuhlman
authors.affiliation: Center for the Physics of Living Cells, University of Illinois at Urbana-Champaign, Urbana, United States.|Department of Physics, University of Illinois at Urbana-Champaign, Urbana, United States.|Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, United States.
authors.forename: Seppe
authors.identifier: 0000-0002-4130-6845
authors.initials: S
authors.lastname: Kuehn
mesh_terms: D000220:Adaptation, Biological; D000073537:Biological Variation, Population; D003470:Culture Media / Q000737:chemistry; D004777:Environment; D004926:Escherichia coli / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*; D008124:Locomotion; D012641:Selection, Genetic
chemical_list: D003470:Culture Media
keywords: E. coli; chemotaxis; computational biology; evolutionary biology; experimental evolution; genomics; phenotypic constraints; phenotypic space; systems biology; trade-off