  Heterozygote disadvantage is potentially a potent driver of population
genetic divergence. Also referred to as underdominance, this phenomena
describes a situation where a genetic heterozygote has a lower overall fitness
than either homozygote. Attention so far has mostly been given to
underdominance within a single population and the maintenance of genetic
differences between two populations exchanging migrants. Here we explore the
dynamics of an underdominant system in a network of multiple discrete, yet
interconnected, populations. Stability of genetic differences in response to
increases in migration in various topological networks is assessed. The network
topology can have a dominant and occasionally non-intuitive influence on the
genetic stability of the system.
