Genomic signatures of the Arctic-adapted North American gray wolf ecotype.

The Arctic Circle is one of Earth's most extreme environments. It features cold temperatures, resource shortages, and near-complete winter darkness. Here, we generated a chromosome-level genome assembly of a male wolf from the Arctic Archipelago (Canis lupus arctos). Our assembly and that of the related C. l. orion from Greenland was used to identify candidate genic and regulatory features of Arctic-adapted polar wolves, ranging from selection acting on standing variation and amino acid changes in genes to conserved non-exonic elements (CNEEs) that may regulate gene expression. We identified genes and nearby CNEEs associated with thermoregulation (e.g., APOB), coat color and patterning (e.g., GOLGB1), and DNA damage response (e.g., POLQ). In vitro assays supported changes in polar wolf gene (POLQ and TRPV2 amino acid substitutions) and CNEE function. Our report offers insights into the genetic mechanisms underlying polar wolf adaptations, laying a foundation for future studies on Arctic canines.