Deleterious Effects of Restricted Gene Flow in Fragmented Populations

I examined the expected detrimental effects of restricted gene flow, a consequence of population fragmentation, through a population genetics model. The model predicts the frequency of deleterious mutations and the viability of the individuals in a set of populations, depending on the number of migrants per generation per population. When the number of migrants is lower than one per generation, a large increase in the viability of the individuals along with the number of migrants is expected. With one migrant per generation, detrimental genetic effects on population survival are expected for low population size or low population growth rate. Finally, the negative effects of restricted gene flow depend not only on the number of migrants entering the population considered but also on the number of migrants entering the populations where the migrants came from.