  We investigate the competition between two quasispecies residing on two
disparate neutral networks. Under the assumption that the two neutral networks
have different topologies and fitness levels, it is the mutation rate that
determines which quasispecies will eventually be driven to extinction. For
small mutation rates, we find that the quasispecies residing on the neutral
network with the lower replication rate will disappear. For higher mutation
rates, however, the faster replicating sequences may be outcompeted by the
slower replicating ones in case the connection density on the second neutral
network is sufficiently high. Our analytical results are in excellent agreement
with flow-reactor simulations of replicating RNA sequences.
