Melanin and methylation: coat color is linked to directional epigenetic shifts in Alaskan wolves

Mammalian coat color has broad eco-evolutionary implications and often co-varies with physiological, behavioral and ecological traits. In wolves, melanism is genetically determined at the K-locus, but whether color morphs differ epigenetically is unknown. Here, we profiled genome-wide DNA methylation in black (N = 48) and gray (N = 99) Alexander Archipelago wolves (Canis lupus ligoni) using reduced-representation sequencing. We identified 880 differentially methylated regions (DMRs) between black and gray wolves, broadly distributed across the genome and representing 3.03% of all loci screened. Strikingly, over 93% of these DMRs were hypermethylated in black wolves, revealing directional, genome-wide shifts in DNA methylation associated with coat color. At the same time, black wolves had lower overall levels of DNA methylation, suggesting that locus-specific hypermethylation occurs against a background of broader hypomethylation. Our findings establish a foundation for future work to elucidate the potential eco-evolutionary significance of color-morph associated epigenetic signatures in natural populations.