Mutational Robustness

Mutational robustness describes the extent to which an organism’s phenotype remains constant in spite of mutation. Natural selection can directly induce the evolution of mutational robustness only when mutation rates are high and population sizes are large. The conditions under which selection could act to directly increase mutational robustness are extremely restrictive, and for this reason, such selection is thought to be limited to only a few viruses and microbes having large population sizes and high mutation rates. However, mutational robustness may evolve as a byproduct of natural selection for robustness to environmental perturbations.

Mutational robustness is thought to be one driver for theoretical viral quasispecies formation.