Yellowstone wolf DNA aids study of Chernobyl packs

Researchers at Princeton University are using genetic data from Yellowstone National Park wolves to investigate how a pack in Ukraine has adapted to decades of nuclear radiation. The study compares wolves living in the Chernobyl exclusion zone with those in other regions, including Wyoming, to identify biological changes that may help the animals resist cancer.

Cara Love, a postdoctoral research associate in Princeton’s Department of Ecology and Evolutionary Biology, said the wolves in the exclusion zone are exposed to radiation levels similar to three or four chest X-rays daily. Conventional science suggests that long-term exposure increases cancer risk, but Love’s team is testing the hypothesis that genetic mutations in these wolves have made them less susceptible to tumors.

To conduct this comparison, scientists needed control samples from populations not exposed to the same environmental hazards. They turned to the Yellowstone wolf population, which Love described as the most studied and best-known group in the world. Blood samples collected from Yellowstone wolves between 2011 and 2013 provided a rich genetic database for the analysis.

The Chernobyl disaster occurred on April 26, 1986, when a reactor exploded during a safety test. The accident killed 31 people in the initial weeks and led to the evacuation of most humans from the roughly 1,000-square-mile zone in Ukraine. With minimal human interference, wildlife has recovered in the area, allowing wolves and other species to thrive in an environment that is otherwise heavily forested.

Love noted that the exclusion zone is home to deer, moose, and European bison. When researchers began trapping and sampling wolves there in 2014, the animals primarily hunted wild boars. A pathogen from nearby domestic farms later decimated the boar population, forcing the wolves to switch to scavenging and hunting other hoofed animals, a dietary shift similar to that seen in Yellowstone.

Radiation in the exclusion zone is present in soil and vegetation. Wolves are exposed directly through their environment and indirectly through the animals they eat. By comparing the Chernobyl wolves to those in Yellowstone and Belarus, researchers identified genetic differences in the Ukrainian pack. These differences included changes in genes related to immune function and the body’s response to cancer-related stress.

Robert Crabtree, founder and president of the Yellowstone Ecological Research Center, said the Yellowstone wolves are invaluable to this work because the park’s open terrain allows for direct observation. Unlike the dense forests of Ukraine, places like Lamar Valley in Yellowstone let researchers track individual packs and their histories over time. This level of data collection is difficult to achieve in other parts of the world.

Crabtree stated that no other wolf population has contributed more to the understanding of wild canines than those in Yellowstone. The findings from the Chernobyl study suggest that rapid genetic evolution can help species adapt to harsh environments. Love said the research may have implications for human health, particularly regarding how the body responds to radiation therapy, though the long-term effects remain an area of active inquiry.