SCIENTISTS STUDYING CHERNOBYL DOGS’ DNA

Researchers looking for genetic effects of radiation exposure

After the disaster at the nuclear power plant in Chernobyl, Ukraine, in 1986, local residents were forced to permanently evacuate, leaving behind their homes and, in some cases, their pets. Concerned that these abandoned animals might spread disease or contaminate humans, officials tried to exterminate them.

And yet, a population of dogs somehow endured. They found fellowship with Chernobyl cleanup crews, and the power plant workers who remained in the area sometimes gave them food. (In recent years, adventurous tourists have dispensed handouts, too.)

Today, hundreds of freeranging dogs live in the area around the site of the disaster, known as the exclusion zone. They roam through the abandoned city of Pripyat and bed down in the highly contaminated Semikhody train station.

Now, scientists have conducted the first deep dive into the animals’ DNA. The dogs of Chernobyl are genetically distinct, different from purebred canines as well as other groups of free-breeding dogs, scientists reported Friday in Science Advances.

It remains too soon to say whether, or how, the radioactive environment has contributed to the unique genetic profiles of the dogs of Chernobyl, scientists said. But the study is the first step in an effort to understand not only how long-term radiation exposure has affected the dogs but also what it takes to survive an environmental catastrophe.

“Do they have mutations that they’ve acquired that allow them to live and breed successfully in this region?” said Elaine Ostrander, a dog genomics expert at the National Human Genome Research Institute and a senior author of the study. “What challenges do they face and how have they coped genetically?”

The project is a collaboration among scientists in the United States, Ukraine and Poland, as well as the Clean Futures Fund, a nonprofit based in the United States that works in Chernobyl. The nonprofit, which was established in 2016, began as an effort to provide health care and support to power plant employees, who still work in the exclusion zone.

But the organization soon realized that Chernobyl’s canine residents needed help, too.

In 2017, the Clean Futures Fund began holding veterinary clinics for the local dogs, providing care, administering vaccines, and spaying and neutering the animals. The researchers piggybacked on these clinics to collect blood samples from 302 dogs living in different locations in and around the exclusion zone.

Nearly half of the dogs lived in the immediate vicinity of the power plant, while the other half lived in Chernobyl City, a lightly occupied residential area about 9 miles away. (A small number of samples came from dogs in Slavutych, a city built for evacuated power plant workers, nearly 30 miles away.)

Although there was some overlap between the canine populations, in general, the power plant dogs were genetically distinct from the Chernobyl City dogs, researchers found. There appeared to be little gene flow between the two groups, suggesting that they rarely interbred.

“I don’t think anybody has looked at a single, freebreeding dog population genetically at this level of detail before,” said Adam Boyko, a canine geneticist at the Cornell University College of Veterinary Medicine, who was not involved in the research.

The study will be a good starting point for further investigation of the effects of radiation, Boyko added.

JORDAN LAPIER VIA THE NYT Scientists are studying the DNA of hundreds of freeranging dogs living in the Chernobyl Exclusion Zone.