After the nuclear power plant disaster After the Chernobyl , Ukraine in 1986, local residents were forced to evacuate permanently, leaving behind their homes and, in some cases, their pets. Concerned that these abandoned animals could spread disease or infect people, authorities have sought to exterminate them.
Yet the dog population somehow survived. They found a common language with the Chernobyl liquidators, and the remaining workstations in the area sometimes fed them. In recent years, enterprising tourists have also been feeding the animals. Today, hundreds of stray dogs live in the area around the disaster site, known as the exclusion zone. They wander through the abandoned city of Pripyat and spend the night in the heavily polluted Semikhody railway station. Now, scientists have conducted the first deep dive into animal DNA. Chernobyl dogs are genetically distinct from purebred canids and other groups of free-breeding dogs, scientists reported March 3 in the journal Science Advances .
It’s still too early to tell whether the radioactive environment contributed to the unique genetic profiles of the Chernobyl dogs, scientists say. But the study is the first step in trying to understand not only how long-term radiation exposure affects dogs, but also what it takes to survive an environmental disaster. ” Have they acquired mutations that allow them to live and reproduce successfully in this region?” said Elaine Ostrander , a canine genomics expert at the National Human Genome Research Institute and senior author of the study. “ What challenges do they face and how did they cope genetically?”
However, before the researchers could answer these questions, they needed to get a sense of the dog’s life under those conditions. “You have this region where there are different levels of radioactivity, where dogs live everywhere,” Dr. Ostrander said. “We needed to know who’s who and what’s what before we started looking for these critical mutations.” The project is the result of a collaboration between US, Ukrainian and Polish scientists, as well as the US-based non-profit Clean Futures Fund working on Chernobyl. The non-profit organization, established in 2016, began its activity by providing medical assistance and support to the workers of the plant, who still work in the exclusion zone.
But the organization quickly realized that Chernobyl victims also needed help. Although the dog population grew in the summer, it often declined in the winter when food was scarce. Anger was a constant problem. Nearly half of the dogs lived in close proximity to the power plant, while the other half lived in Chernobyl, a sparsely populated residential area about 14km away. A small number of samples were taken by dogs in Slavutych, a town built for evacuated plant workers, which is nearly 50km from the plant.
The researchers found that while there was some overlap between dog populations, overall, the power plant dogs were genetically different from the Chernobyl dogs. There appears to have been little gene flow between the two groups, suggesting that they rarely interbred. The researchers noted that physical safety barriers around the power plant may have helped keep the dogs apart.
“I was quite surprised by the almost complete differentiation between the two populations, by the fact that they’ve actually existed in relative isolation for quite some time ,” said Timothy Musso , a biologist at the University of South Carolina and another senior author. of study. The researchers also tracked parentage, linking parents and children to identify 15 different family groups. Some dog families were large and sprawling, while others were tiny, with more defined geographical areas. Scientists found that three family groups lived near the spent nuclear fuel storage facility.
“I don’t think anyone has previously examined the genetic population of free-range dogs with this level of detail ,” said Adam Boyko , a dog geneticist at Cornell University’s College of Veterinary Medicine who was not involved in the study. The study will be a good starting point for further study of the effects of radiation, said Dr. Boyko. ” They find interesting populations ,” he said, ” interesting family groups .”
The power plant dogs and the city dogs were of mixed ancestry. They shared DNA traits with German Shepherds, as well as other Eastern European Shepherd breeds. Even the dogs of the city of Chernobyl had characteristic variants of Boxers and Rottweilers. These segments of DNA could provide particularly useful data in future studies, the scientists say. Comparing these sequences in power plant dogs, Chernobyl dogs, and purebred herding dogs living in a non-radioactive environment could help researchers identify changes in the genome associated with radiation. ” This is a unique opportunity ,” Dr. Musso said, “a unique animal population . “
