Restricted dispersal determines fine-scale spatial genetic structure of Mongolian gerbils

Restricted gene flow may cause positive spatial genetic autocorrelation of animal populations at fine spatial scales. The Mongolian gerbil Meriones unguiculatus is a territorial, social rodent. Territoriality may create social fences to restrict dispersal or gene flow of Mongolian gerbils to a short distance. Restricted dispersal may differentiate fine-scale spatial genetic structure of populations with increasing distances (i.e., isolation by distance [IBD]). Competition for mates and inbreeding avoidance may result in equal dispersal propensity and subsequently similar spatial genetic autocorrelation between males and females of monogamous gerbils. We genotyped 327 gerbils, live captured from 26 burrow systems on a 9-ha plot in northcentral Inner Mongolia, China, using seven microsatellite loci. Spatial genetic autocorrelation was positive within 80 m and became negative from 80 m to 200 m, suggesting restricted gene flow. Inter-group genetic and geographic distances were related positively, supporting the IBD model. Live trapping data demonstrated equal dispersal propensities of male and female gerbils. Restricted dispersal and social organization may determine fine-scale spatial population genetic structure of social rodents.