Fine-scale genetic structure in Ethiopian wolves imposed by sociality, migration, and population bottlenecks

Abstract

We used demographic, spatial, and microsatellite data to assess fine-scale genetic structure in Ethiopian wolves found in the Bale Mountains and evaluated the impact of historical versus recent demographic processes on genetic variation. We applied several analytical methods, assuming equilibrium and nonequilibrium conditions, to assess demography and genetic structure. Genetic variation (HE = 0.584-0.607, allelic richness = 4.2-4.3) was higher than previously reported for this species and genetic structure was influenced by geography and social structure. Statistically significant FST values (0.06-0.08) implied differentiation among subpopulations. STRUCTURE analyses showed that neighbouring packs often have shared co-ancestry and spatial autocorrelation showed higher genetic similarity between individuals within packs and between individuals in neighbouring packs compared to random pairs of individuals. Recent effective population sizes were lower than 2n (where n is the number of packs) and lower than the number of breeding individuals with Ne/N ratios near 0.20. All subpopulations have experienced bottlenecks, one occurring due to a rabies outbreak in 2003. Nevertheless, differentiation among these subpopulations is consistent with long-term migration rates and fragmentation at the end of the Pleistocene. Enhanced drift due to population bottlenecks may be countered by higher migration into disease-affected subpopulations. Contemporary factors such as social structure and population bottlenecks are clearly influencing the level and distribution of genetic variation in this population, which has implications for its conservation. © Springer Science+Business Media B.V. 2009.