Chernobyl dogs are showing signs of major genetic differences - but not for the reason you'd think

Mutations caused by radiation may not be the reason for genetic differences seen in dog populations that live close to the Chernobyl nuclear power plant, according to a brand new study.

The research, which was published on Monday in the journal PLOS One, has implications for how we understand the effects of nuclear radiation exposure on populations.

On April 26, 1986 at the plant in Chernobyl, Ukraine, the reactor overheated, melted through protective barriers, and exploded, releasing deadly radiation into the atmosphere. Two workers were killed by the explosion and 28 firemen and emergency clean-up crew died from acute radiation poisoning in the three months that followed after the explosion.

Chernobyl dogs are evolving – and even have unique genetics Dimitar Dilkoff/AFP via Getty Images

Scientists have been studying dog populations as well as the surroundings near the nuclear power plant ever since the disaster happened to understand the long-term impact of radiation leaks.

“We are trying to determine if low-level exposure over many years to environmental toxins such as radiation, lead, etcetera, could explain some of those differences,” another study co-author Matthew Breen from the North Carolina State University said.

A previous study analysed genetic variants in the genomes of dogs near the nuclear plant. It identified 391 outlier DNA segments that differed between two populations.

Some of these genome sections contained genes that contributed to the repair of DNA damage.

Scientists looked deeper into the genomes of the dogs in the new research to detect evidence of mutations that may have accumulated over time and to contextualise the level of differences.

The analysis indicated that the genetics of dogs from the city of Chernobyl were very similar to dog populations in Russia, Poland and the surrounding areas.

This finding helped researchers use the Chernobyl city dogs as a control population to compare with dogs living closer to the nuclear power plant.

Researchers looked for abnormalities in reproductive cell DNA, which is passed from parents to their offspring.

“While this dog population is 30 or more generations removed from the one present during the 1986 disaster, mutations would likely still be detectable if they conferred a survival advantage to those original dogs,” Dr Breen said.

Researchers did not find any such evidence in these dogs. However, this does not rule out the possibility that environmental pressures had a role in bringing about the differences between the two dog populations.

“It’s possible that the dogs that survived long enough to breed already had genetic traits that increased their ability to survive,” said Megan Dillon, a PhD candidate at NC State University who was part of the study. “So perhaps there was extreme selective pressure at the start, and then the dogs at the power plant just remained separate from the city population.”

Norman Kleiman, a co-author of the study, said: “The importance of continuing to study the environmental health aspects of large-scale disasters like this cannot be overemphasized.

“Studying companion animals like these dogs offers a window into the kinds of adverse health risks that people may face.”

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