Abstracts (first author)
Modeling plastic and canalized phenotypic expression by the process of genetic accommodation
The evolution of polyphenism, in which a single genotype produces alternative discrete phenotypes in response to environmental cues, and the evolution of a novel canalized phenotype, in which a genotype produces a novel, invariant phenotype in spite of environmental differences, represent different end points in the process of genetic accommodation. Genetic accommodation is hypothesized to begin when heritable variation in developmental switch points and environmental variation conspire to trigger the expression of a novel phenotype, thus exposing the underlying genetic variation to selection. We model genetic accommodation using a threshold model. Using simulations, we illustrate the model by application to the evolution of both the environmentally induced expression of a novel defensive phenotype and the evolution of the canalized expression of a defensive phenotype. We show that, given the appropriate ecological and genetic conditions, genetic accommodation can occur rapidly, resulting in the evolution of either polyphenism or a novel canalized phenotype.