Effect of population patchiness and migration rates on the adaptation and divergence of vesicular stomatitis virus quasispecies populations

The effect of migration among different isolated virus quasispecies populat ions on their adaptation and diversity was analysed through experimental ev olution. An in vitro cell system was employed to simulate migration of vesi cular stomatitis virus between isolated homogeneous host cell populations. The results clearly demonstrated a positive correlation between the migrati on rate and the magnitude of the mean fitness reached by the virus quasispe cies populations. The results also showed, although less clearly, that fitn ess differences among quasispecies decreased with the magnitude of migratio n. These results are in close agreement with predictions of standard popula tion genetics theory. These results can be explained in terms of the spread of beneficial mutations, originating in a single isolated quasispecies, th rough the entire system formed by the different quasispecies populations co ntained in different host cell populations.