Comparative spatial genetic structure of two rodent species in an agro-ecological landscape in southern Africa

Abstract

Determining the scale of genetic variation informs studies of dispersal, connectivity, and population dynamics particularly in heterogeneous landscapes. Mastomys natalensis and Mus minutoides are generalist rodents that utilize multiple habitat types within the agro-ecological landscapes of southern African savannas. To study the comparative spatial genetic structure of these species we developed 9 new microsatellites for Mus and used 14 microsatellite loci previously developed for Mastomys, to genotype rodents sampled across an agro-ecological landscape (˜200 km2). Spatial genetic structure was measured using spatial autocorrelation and Moran’s Eigenvector Maps analysis. In both species, non-random genetic similarity was limited to only the smallest spatial scales (<600 m), and at that scale, it was significantly greater in Mastomys than in Mus. Only a small proportion of the genetic signal across the landscape was due to spatial signal in Mastomys, and there was no spatial signal detected for Mus. The lack of spatial autocorrelation beyond the first six hundred meters for both species illustrated that they are capable of high rates of dispersal, while the observed patterns of genetic panmixia found for both species is the predicted genetic outcome for species with omnivorous habits and plastic habitat use. These findings have implications for both pest management and rodent-borne disease control.