Environment determines evolutionary trajectory in a constrained phenotypic space

Elife. 2017 Mar 27;6:e24669. doi: 10.7554/eLife.24669.


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 select Escherichia coli for 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.

Keywords: E. coli; chemotaxis; computational biology; evolutionary biology; experimental evolution; genomics; phenotypic constraints; phenotypic space; systems biology; trade-off.

MeSH terms

  • Adaptation, Biological*
  • Biological Variation, Population*
  • Culture Media / chemistry
  • Environment*
  • Escherichia coli / genetics*
  • Escherichia coli / growth & development
  • Escherichia coli / physiology*
  • Locomotion
  • Selection, Genetic


  • Culture Media

Grant support

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.