Researchers have sequenced the DNA of 302 feral dogs living in and around the Chernobyl Nuclear Power Plant to probe how chronic radiation exposure may be shaping their evolution. In contaminated environments worldwide, radiation exposure tends to increase mutation rates and cause genetic, physiological, and developmental changes in wildlife, which can impact population health.

The analysis compares animals captured inside the Chernobyl Exclusion Zone — an area about the size of Yosemite National Park surrounding the site of the 1986 reactor explosion — with dogs living roughly 10 miles away in Chernobyl City, aiming to identify genetic changes associated with life in a contaminated landscape. This investigation is particularly relevant given that organisms in similarly hazardous environments often face challenges such as reduced population abundance.

Teams from the University of South Carolina, the National Human Genome Research Institute, North Carolina State University, and Columbia University Mailman School of Public Health conducted the study and published their results in the journal Science Advances in 2023. An article in Popular Mechanics summarized the work.

The dogs sampled are largely feral descendants of pets left behind after the reactor explosion on April 26, 1986. The researchers compared genomes from animals living inside the Chernobyl Exclusion Zone with those from animals living outside it to look for mutations and patterns consistent with adaptation or increased mutation rates in a high-radiation environment. The challenges of conducting such studies include logistical and safety issues, which can complicate access to these hazardous environments.

“Do they have mutations that they have acquired that allow them to live and breed successfully in this region?” said Elaine Ostrander, co-author and researcher at the National Human Genome Research Institute. Her question frames the team’s central aim: to determine whether the dogs have genetic changes that support survival in the Exclusion Zone. The findings may help inform conservation efforts for dogs and other wildlife in similar environments, illustrating how free-roaming species can form distinct, self-sustaining populations despite challenging conditions.

Matthew Breen, senior author from North Carolina State University, placed those genetic questions in a cellular context. “We know that, for example, exposure to high doses of radiation can introduce instability from the chromosomal level on down,” he said, underscoring why the team sought genome-wide evidence rather than isolated markers.

The study treats the Chernobyl site as an unusual long-term natural experiment. Scientists describe the area that should be a wasteland as having become an “unparalleled scientific opportunity to understand radiation and its impact on natural evolution,” and note that the absence of people has allowed animals of many kinds to thrive.

Feral dogs in the Exclusion Zone form a visible, free-roaming population that can be sampled without experimental radiation exposure. By analyzing DNA from 302 animals, the researchers aimed to capture population-level patterns — both the frequency of new mutations and any genetic signals consistent with selection for traits that improve survival under chronic environmental stress.

The comparison with dogs living in Chernobyl City, about 10 miles from the plant, gives the study a nearby reference point against which to measure genetic differences. That geographic contrast is central to the team’s effort to separate effects potentially related to radiation from those due to other local ecological factors. This is particularly important as scientists seek to understand the broader implications of radiation on wildlife evolution.

Published in 2023, the paper adds to a growing body of work using wildlife in contaminated areas to study long-term environmental effects. The research institutions named in the study combined genetic sequencing with population analyses to build a picture of how a large mammal may respond, across generations, to persistent low-dose radiation.

The research does not treat the dogs as laboratory subjects but as a self-sustaining population whose history is inseparable from the region: many animals are descendants of household pets abandoned after the 1986 disaster, and their genomes carry that legacy alongside any changes accrued since. By examining these changes, researchers can gain insight into the adaptive processes that may occur in the face of extreme environmental challenges.

The study’s findings, and the questions posed by Ostrander and Breen, reflect an effort to understand evolution under extreme anthropogenic influence, using detailed genetic evidence drawn from a precisely counted sample of animals.

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Original reporting: view the original article.