Bistability in feedback circuits as a byproduct of evolution of evolvability

Hiroyuki Kuwahara, Orkun S. Soyer*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


Noisy bistable dynamics in gene regulation can underlie stochastic switching and is demonstrated to be beneficial under fluctuating environments. It is not known, however, if fluctuating selection alone can result in bistable dynamics. Using a stochastic model of simple feedback networks, we apply fluctuating selection on gene expression and run in silico evolutionary simulations. We find that independent of the specific nature of the environment-fitness relationship, the main outcome of fluctuating selection is the evolution of increased evolvability in the network; system parameters evolve toward a nonlinear regime where phenotypic diversity is increased and small changes in genotype cause large changes in expression level. In the presence of noise, the evolution of increased nonlinearity results in the emergence and maintenance of bistability. Our results provide the first direct evidence that bistability and stochastic switching in a gene regulatory network can emerge as a mechanism to cope with fluctuating environments. They strongly suggest that such emergence occurs as a byproduct of evolution of evolvability and exploitation of noise by evolution.

Original languageEnglish (US)
Article number564
JournalMolecular Systems Biology
StatePublished - 2012


  • environmental fluctuations
  • gene regulatory network
  • noise
  • phenotypic variability
  • stochastic switching

ASJC Scopus subject areas

  • Information Systems
  • General Immunology and Microbiology
  • Applied Mathematics
  • General Biochemistry, Genetics and Molecular Biology
  • General Agricultural and Biological Sciences
  • Computational Theory and Mathematics


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