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