On the Origin of Phenotypic Plasticity

Abstract Phenotypic plasticity provides an attractive strategy for adapting to various environments, but its evolutionary origin is poorly understood. We use a simple gene regulatory network model to explore how phenotypic plasticity arises. The model assumes two alternative types of environments, while the network includes a gene that turns on and off depending on the type of environment. With this assumption, we demonstrate that the system gradually adapts by acquiring the ability to produce two distinct optimum phenotypes under two types of environments without changing genotype, thus resulting in phenotypic plasticity. Our results indicate that gene regulatory networks have a marked ability to flexibly produce various phenotypes in response to environmental changes. Moreover phenotypic evolution may be better modeled by a gene regulatory network, rather than a single gene underlying a focal phenotype.