CONCLUSIONS
As global climate change becomes an increasing threat to biodiversity, our understanding of the adaptive potential of species and the integration of this information into management strategies will be critical in preventing species loss. Thus, determining the rates and mechanisms of species responding to environmental change is an important goal for the conservation of species at risk. Our use of a candidate gene approach allowed for the a priori selection of a gene with characterized functions, which we hypothesized to be under selection in our species of interest, Canada lynx. We detected multiple signatures of selection in both an intra-specific comparison of closely-related species (Canada lynx and bobcat), and inter-specifically in Canada lynx at the NR1D1 clock gene cTNR. The possibility for hybrid-mediated gene flow via introgression between lynx and bobcats can erode the pure genomes of the parental species, and can carry positive and/ or negative consequences by, for example, facilitating the northward range expansion of bobcats. The small yet significant influence of both environment and space on this clock gene locus within the eastern distribution of lynx suggests that environmental factors are influencing the distribution of genetic variation at this locus, some of which may be tightly correlated with space (i.e., latitude). More broadly, signatures of selection on the NR1D1 locus within lynx suggests that cTNR loci may play a role in generating functional diversity within mammals that can be influenced by selection. Ultimately, the high mutation rates of cTNR loci may allow for contemporary rates of evolution in wild populations. While selection on cTNR loci has already been suggested in wild populations of birds (Johnsen et al., 2007; Liedvogel et al., 2009) and fish (e.g., O’Malley et al., 2010), to our knowledge this is the first report that provides evidence for selection on a cTNR locus in a highly vagile wild mammal. Although cTNRs are largely under-represented in the wildlife literature, they may be important targets of study for those aiming to understand the rapid adaptive potential of species under environmental change.