Chernobyl Dogs Show Signs of Natural Selection, but the Cause Remains Unclear
A study in the scientific journal Genes finds that dogs around the Chernobyl nuclear plant differ genetically from other dogs in a way chance alone cannot explain. The researchers cannot say which environmental factor drove the change.
Researchers analyzing the DNA of dogs living around the Chernobyl nuclear power plant disaster site in Ukraine have concluded that natural selection has likely shaped the animals' genetic profile. The findings, published in the scientific journal Genes, matter because they hint at how animals can adapt to a contaminated environment, although the exact cause is still unknown.
What was compared
The team compared DNA from dogs living right next to the plant with samples from dogs in the city of Chernobyl, roughly 16 kilometers away. Both groups were also compared with dog populations elsewhere in the world. The differences were stark: first author Megan Dillon, a postdoctoral researcher at North Carolina State University, said the city's dogs are genetically closer to dogs in the Galapagos Islands than to the population at the plant.
The analysis showed that random genetic drift alone could not account for the differences. Some of the genomic regions under the strongest selective pressure are linked to DNA repair, immunity and cell survival.
Not new mutations
According to the researchers, these variants probably already existed among local dogs and became more common over the past 40 years, rather than arising as new mutations. Dillon suggested the founding population may already have had enough genetic diversity to survive harsh conditions.
What remains unknown
The researchers cannot say the changes are tied to radiation specifically. Chernobyl's dogs descend from pets left behind during the evacuations, and they have also endured harsh winters, heavy metals and pesticides. Dillon said there are too many variables to isolate a single one.
Senior author Matthew Breen, a professor of genomics at North Carolina State University, noted that no samples from earlier years exist, so the data is like a single still image. In 1986, no organism had yet had its full genome sequenced.
The accident's exclusion zone is now also home to wolves, deer, wild boars and lynx. Researchers have observed similar genomic distinctions in some of these animals, such as wolves.
