Robustness and epistasis in mutation-selection models.
We investigate the fitness advantage associated with the robustness of a phenotype against deleterious mutations using deterministic mutation-selection models of a quasispecies type equipped with a mesa-shaped fitness landscape. We obtain analytic results for the robustness effect which become exact in the limit of infinite sequence length. Thereby, we are able to clarify a seeming contradiction between recent rigorous work and an earlier heuristic treatment based on mapping to a Schrödinger equation. We exploit the quantum mechanical analogy to calculate a correction term for finite sequence lengths and verify our analytic results by numerical studies. In addition, we investigate the occurrence of an error threshold for a general class of epistatic landscapes and show that diminishing epistasis is a necessary but not sufficient condition for error threshold behaviour.
Institut für Theoretische Physik, Universität zu Köln, Köln, Germany. awolff@thp.uni-koeln.de
Andrea
A
Wolff
Joachim
J
Krug
D004843:Epistasis, Genetic / Q000235:genetics*; D008957:Models, Genetic; D009154:Mutation / Q000235:genetics*; D010641:Phenotype