Nearly four decades after the Chernobyl nuclear disaster, researchers have found evidence that dogs living near the abandoned power plant have undergone genetic changes that may reflect natural selection.
The study, published in Genes under the title ‘Evidence of Selective Response in the Free-Breeding Dog Population in Chornobyl’, examined the genomes of free-breeding dogs living near the nuclear power plant and compared them with those of dogs in the city of Chernobyl, approximately 16 kilometres away, as well as other dog populations from around the world.
The researchers found that the two populations were genetically distinct. Megan Dillon, the study’s first author and a postdoctoral researcher at North Carolina State University, told WIRED that dogs in Chernobyl city were “more genetically similar to dogs in the Galápagos Islands” than to those living near the power plant.
Evidence of natural selection
The researchers investigated whether this difference could be explained by genetic drift, the random changes in gene frequencies that occur in relatively small populations, or by natural selection, in which inherited traits become more common because they offer a survival or reproductive advantage.
Their analysis identified more than 100 candidate loci showing evidence of positive selection in the power plant population. These regions included genes associated with DNA replication and repair, immune responses, cell survival and cancer-related pathways.
The findings suggest that natural selection, rather than random genetic drift alone, may have contributed to the population’s distinctive genetic profile. The researchers propose that genetic variations already present among the dogs’ ancestors may have helped some individuals survive and reproduce under difficult environmental conditions.
Dillon cautioned, however, that “we still cannot say that this is tied to the exposures that the dogs have faced”.
Radiation not the only possible explanation
The 1986 disaster released radioactive material into the surrounding environment, but the exclusion zone has also been contaminated by heavy metals, pesticides and other pollutants. The dogs are largely descended from pets left behind during the evacuation of nearby settlements.
Dillon told WIRED that the different contaminants can produce overlapping biological effects, making it difficult to identify a single cause. The researchers also lack genetic samples from the dogs that lived in the area immediately after the accident. As senior author Matthew Breen explained, studying the present-day population is “almost like looking at a single still image and trying to figure out what came before it”.
The study estimates that the population may have undergone significant selection over approximately 35 generations. However, it cannot establish precisely when the changes occurred or which environmental pressures drove them.
The findings do not demonstrate that radiation has produced beneficial mutations in the dogs, nor that the animals are immune to its effects. Instead, they provide evidence that natural selection may have shaped the population’s genetic makeup over successive generations.
The researchers say further genetic and physiological studies could help clarify how animals respond to long-term environmental contamination, with potential implications for understanding susceptibility to environmental hazards in other species, including humans.
(Edited By Raunaq Lekhi)