Phenotypic robustness can increase phenotypic variability after non-genetic perturbations in gene regulatory circuits

Carlos Espinosa-Soto 1, 2, Olivier C. Martin 3, 4, Andreas Wagner 1, 2, 5

Journal of Evolutionary Biology 24 (2011) 1284-1297

Non-genetic perturbations, such as environmental change or developmental noise, can induce novel phenotypes. If an induced phenotype confers a fitness advantage, selection may promote its genetic stabilization. Non-genetic perturbations can thus initiate evolutionary innovation. Genetic variation that is not usually phenotypically visible may play an important role in this process. Populations under stabilizing selection on a phenotype that is robust to mutations can accumulate such variation. After non-genetic perturbations, this variation can become a source of new phenotypes. We here study the relationship between a phenotype's robustness to mutations and a population's potential to generate novel phenotypic variation. To this end, we use a well-studied model of transcriptional regulation circuits. Such circuits are important in many evolutionary innovations. We find that phenotypic robustness promotes phenotypic variability in response to non-genetic perturbations, but not in response to mutation. Our work suggests that non-genetic perturbations may initiate innovation more frequently in mutationally robust gene expression traits.

  • 1. Department of Biochemistry,
    University of Zurich
  • 2. Swiss Institute of Bioinformatics (SIB),
    Swiss Institute of Bioinformatics
  • 3. Laboratoire de Physique Théorique et Modèles Statistiques (LPTMS),
    CNRS : UMR8626 – Université Paris XI - Paris Sud
  • 4. Laboratoire de Génétique Végétale du Moulon,
    Université Paris XI - Paris Sud
  • 5. Santa Fe Institute,
    Santa Fe Institute