Environmental Dependence of Genetic Constraint

Marjon G J de Vos, Frank J. Poelwijk, Nico Battich, Joseph D T Ndika, Sander J. Tans

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

The epistatic interactions that underlie evolutionary constraint have mainly been studied for constant external conditions. However, environmental changes may modulate epistasis and hence affect genetic constraints. Here we investigate genetic constraints in the adaptive evolution of a novel regulatory function in variable environments, using the lac repressor, LacI, as a model system. We have systematically reconstructed mutational trajectories from wild type LacI to three different variants that each exhibit an inverse response to the inducing ligand IPTG, and analyzed the higher-order interactions between genetic and environmental changes. We find epistasis to depend strongly on the environment. As a result, mutational steps essential to inversion but inaccessible by positive selection in one environment, become accessible in another. We present a graphical method to analyze the observed complex higher-order interactions between multiple mutations and environmental change, and show how the interactions can be explained by a combination of mutational effects on allostery and thermodynamic stability. This dependency of genetic constraint on the environment should fundamentally affect evolutionary dynamics and affects the interpretation of phylogenetic data.

Original languageEnglish (US)
Article numbere1003580
JournalPLoS genetics
Volume9
Issue number6
DOIs
StatePublished - Jun 1 2013

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Molecular Biology
  • Genetics
  • Genetics(clinical)
  • Cancer Research

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    de Vos, M. G. J., Poelwijk, F. J., Battich, N., Ndika, J. D. T., & Tans, S. J. (2013). Environmental Dependence of Genetic Constraint. PLoS genetics, 9(6), [e1003580]. https://doi.org/10.1371/journal.pgen.1003580