Evolutionary Benefits of Fitness-Dependent Mutation Rates

Motivated by recent observations that mutation rates can be correlated with individual fitness, we analyze an evolutionary hill-climbing model with fitness-dependent mutation rates. Our results show that a mutation rate that decreases with increasing relative fitness can greatly accelerate the accumulation of beneficial mutations. Moreover, we show that a lower mutation rate for fitter individuals can prevent "mutational meltdown"of small populations by decreasing the probability of fixation of deleterious mutations. These findings suggest potential strategies for accelerating the adaptation of populations to environmental changes.