Introduction history overrides social factors in explaining genetic structure of females in Mediterranean mouflon

Fine-scale spatial genetic structure of populations results from social and spatial behaviors of individuals such as sex-biased dispersal and philopatry. However, the demographic history of a given population can override such socio-spatial factors in shaping genetic variability when bottlenecks or founder events occurred in the population. Here, we investigated whether socio-spatial organization determines the fine-scale genetic structure for both sexes in a Mediterranean mouflon (Ovis gmelini musimon × Ovis sp.) population in southern France 60 years after its introduction. Based on multilocus genotypes at 16 loci of microsatellite DNA (n = 230 individuals), we identified three genetic groups for females and two for males, and concurrently defined the same number of socio-spatial units using both GPS-collared individuals (n = 121) and visual resightings of marked individuals (n = 378). The socio-spatial and genetic structures did not match, indicating that the former was not the main driver of the latter for both sexes. Beyond this structural mismatch, we found significant, yet low, genetic differentiation among female socio-spatial groups, and no genetic differentiation in males, with this suggesting female philopatry and male-biased gene flow, respectively. Despite spatial disconnection, females from the north of the study area were genetically closer to females from the south, as indicated by the spatial analysis of the genetic variability, and this pattern was in accordance with the common genetic origin of their founders. To conclude, more than 14 generations later, genetic signatures of first introduction are not only still detectable among females, but they also represent the main factor shaping their present-time genetic structure.