Population genetic structure of the common warthog (Phacochoerus africanus) in Uganda: evidence for a strong philopatry among warthogs and social structure breakdown in a disturbed population

摘要

Fine-scale genetic structure of large mammals is rarely analysed. Yet it is potentially important in estimating gene flow between the now fragmented wildlife habitats and in predicting re-colonization following local extinction events. In this study,we examined the extent to which warthog populations from five localities in Uganda are genetically structured using both mitochondrial control region sequence and microsatellite allele length variation. Four of the localities (Queen Elizabeth, MurchisonFalls, Lake Mburo and Kidepo Valley) are national parks with relatively good wildlife protection practices and the other (Luwero), not a protected area, is characterized by a great deal of hunting. In the total sample, significant genetic differentiationwas observed at both the mtDNA locus (F_(ST) = 0.68; P < 0.001) and the microsatellite loci (F_(ST) = 0.14; P < 0.001). Despite the relatively short geographical distances between populations, significant genetic differentiation was observed in all pair-wise population comparisons at the two marker sets (mtDNA F_(ST) = 0.21-0.79, P < 0.001; microsatellite F_(ST) = 0.074-0.191, P < 0.001). Significant heterozygote deficiency was observed at most loci within protected areas while no significant deviationfrom Hardy-Weinberg expectation was observed in the unprotected Luwero population. We explain these results in terms of: (i) a strong philopatry among warthogs, (ii) a Wahlund effect resulting from the sampling regime and (iii) break down of social structure in the disturbed Luwero population.