Genes Linked to White-Tailed Jackrabbits' Winter Coat Color Change

The genetic underpinnings of the white-tailed jackrabbits' ability to change their coat color in winter are reported in Science this week, giving new insights into adaptive traits and how the animals might respond to climate change. The white-tailed jackrabbit is one of several species that experience seasonal coat color changes, with its fur becoming white in winter to match snow-covered environments to help it hide from predators. However, snow declines linked to climate change could result in camouflage mismatch and leave the rabbits vulnerable to predation. To better understand the genetic basis of this color shift and the future adaptive potential of winter camouflage in white-tailed jackrabbits, a team led by scientists from the University of Montana built a probabilistic model to show that winter coat color tracks variation in snow cover across the white-tailed jackrabbit's geographic range. The researchers also sequenced 74 jackrabbit genomes, revealing three genes that are primarily responsible for seasonal coat color variations in the animals. "Winter color variation was associated with deeply divergent alleles at these genes, reflecting selection on both ancestral and introgressed variation," the study's authors write. The scientists predict that forecasted reductions in snow cover are likely to induce widespread camouflage mismatch, but that white-tailed jackrabbit populations with variations for darker winter coats are likely to rapidly adapt, providing a trait-based genetic framework to facilitate evolutionary rescue.