Chernobyl’s Feral Dogs Show Clear Genetic Shifts — Radiation Link Still Unproven

Chernobyl’s Feral Dogs Reveal Genetic Differences, But Cause Remains Unclear

Decades after the April 26, 1986 reactor disaster left the area around Chernobyl largely uninhabited by people, thousands of feral dogs roam the Exclusion Zone. Scientists have used these animals as living indicators to study how long-term exposure to radioactive contamination might shape genomes, health and evolution.

What researchers did: A team from the University of South Carolina and the National Human Genome Research Institute sequenced DNA from 302 feral dogs found inside and near the Chernobyl Exclusion Zone (CEZ) and compared those genomes with dogs about 10 miles away in Chernobyl City. Their 2023 paper in Science Advances reported distinct genetic differences between the two groups.

What they found: The genomes of dogs living inside or adjacent to the power plant area showed patterns that set them apart from the nearby control population. Co-author Elaine Ostrander noted researchers are asking whether these differences include mutations that help dogs survive and reproduce in the contaminated environment.

“Do they have mutations that they’ve acquired that allow them to live and breed successfully in this region? What challenges do they face and how have they coped genetically?” — Elaine Ostrander

Conflicting evidence: Follow-up work has produced different conclusions. A later, comprehensive analysis by teams at North Carolina State University and Columbia University (published in PLOS One) examined chromosomes, whole genomes and nucleotide sequences and reported no clear signatures of radiation-induced mutation in the Chernobyl dogs. That study used dogs from Chernobyl City and other regional populations as controls and argued that, if strongly beneficial radiation-driven mutations had arisen, they would likely still be detectable even after many dog generations.

Why the disagreement? Distinguishing mutations caused by radiation from population effects such as inbreeding, genetic drift, founder effects or selection for non-radiation environmental pressures is difficult. Low sample sizes in particular subgroups, complex population histories and the many generations since 1986 complicate causal inference. Small-species studies at Chernobyl — for example, a 2016 report of darker-colored Eastern tree frogs inside the CEZ — show that local genetic or phenotypic changes can occur, but mechanisms and drivers vary by species and context.

What this means: The 2023 genomic survey provides a valuable baseline for larger-mammal genetic research in contaminated ecosystems, even if it does not definitively tie observed differences to radiation exposure. The CEZ remains an important, if imperfect, natural laboratory to study long-term ecological and genetic responses to nuclear contamination.

Next steps for researchers

Future work should combine larger sample sizes, long-term monitoring, detailed pedigree and demographic data, environmental-dose reconstructions, and functional studies that test whether identified variants affect survival or radiation tolerance. Only with multiple independent lines of evidence can scientists more confidently separate radiation-driven evolution from other genetic forces.

Bottom line: Chernobyl’s feral dogs show genetic distinctions from nearby populations, but whether those changes are caused by chronic radiation exposure remains unresolved. The zone continues to offer a unique opportunity to study how severe environmental disruption can shape animal populations over time.