Mitochondrial DNA diversity and phylogeography of insular Newfoundland red foxes (Vulpes vulpes deletrix)

As the only native insular Newfoundland, Canada, canid from the extinction of the wolf in the 1930s to the recent arrival of coyotes, the red fox (Vulpes vulpes deletrix) poses interesting questions about genetic distinctiveness and the postglacial colonization history of the island's depauperate mammalian fauna. Here, we characterize genetic variability at the mitochondrial control region in 189 foxes from the island of Newfoundland, Prince Edward Island, and Labrador. We identified 8 haplotypes (3 new to this study) defined by 11 polymorphic sites, with an average pairwise sequence divergence of similar to 0.003 and haplotypic diversity of 0.56 among localities. A pairwise distribution of control region sequence differences, rho estimate of divergence time, and tests of neutrality (Fu's F-S and Tajima's D) are weakly consistent with a population expansion similar to 9,000 years ago, correlating with retreat of glacial ice from the region. Haplotype composition reflects primarily the Eastern subclade of Aubry and colleagues and supports Aubry's 2-refugia hypothesis that indigenous red foxes in North America are derived from disparate refugia isolated during the Wisconsinan glaciation. Haplotype identity and pattern of population differentiation suggest recolonization of the island of Newfoundland via a northern glacial refugium via Quebec or Labrador rather than an Atlantic or southern route, but provide no mitochondrial genetic evidence to support differentiation of this population of foxes along subspecies lines. We establish a baseline for continued investigations of population demography, genetic structure, and adaptive genetic diversity in island Newfoundland red foxes, a population of interest from both ecological and wildlife disease perspectives.