The consumption of marine subsidies is associated with genome-wide patterns of DNA methylation in Alaskan coastal wolves (Canis lupus ligoni)

Alexander Archipelago wolves are an ecologically and genetically distinct subspecies of gray wolf endemic to the coastal regions of Southeast Alaska. Post-logging forest succession has led to the depletion of Alexander Archipelago wolves’ primary prey - Sitka black-tailed deer. The use of marine prey by some wolves has been suggested to increase population resilience to declines in ungulate prey, yet little is known about the molecular mechanisms mediating this dietary shift. Environmentally sensitive epigenetic modifications, such as DNA methylation, provide an important avenue through which ecological effects can impact animal behavior. Yet, the relationship between DNA methylation and diet has not been explored in wild carnivores, leaving questions about the sensitivity of epigenetic modifications to dietary processes unanswered. To address this gap, we profiled genome-wide DNA methylation among 152 Alexander Archipelago wolves and coupled this data with information on wolves’ diet. K-means clustering grouped wolves into three dietary clusters corresponding to wolves’ use of marine versus terrestrial sourced prey. We detected 1,263 differentially methylated regions (DMRs) between wolves from these dietary clusters. Compared to terrestrial wolves, marine-oriented wolves were hypermethylated at 96% of DMRs, possibly reflecting a higher consumption of marine derived polyunsaturated fatty acids. DMRs associated with diet were distinct from those associated with neutral genetic variation, suggesting that patterns of DNA methylation can distinguish between aspects of diversity related to diet versus genetic population structure. Our findings suggest that DNA methylation could represent an important molecular marker to investigate population differences in ecologically relevant behavioral traits.