About a three states molecular evolution model.

The Eigen model of molecular evolution has recently been reconsidered by taking into account the existence of non-reproducing sequences. New results obtained with this model are presented here: several time-scales characterize the population dynamics and the location of the error threshold, shifted towards larger values of the probability of mutation, depends on both the size of the population and time. Thus this model can be used to analyse extinction events. The distribution of individuals in sequence space beyond the threshold is also discussed.