  Using methods of statistical physics, we present rigorous theoretical
calculations of Eigen's quasispecies theory with the truncated fitness
landscape which dramatically limits the available sequence space of a
reproducing quasispecies. Depending on the mutation rates, we observe three
phases, a selective one, an intermediate one with some residual order and a
completely randomized phase. Our results are applicable for the general case of
fitness landscape.

Populations and Evolution;Quantitative Methods