In the early hours of April 26, 1986, two explosions occurred at a nuclear power plant near the Ukrainian city of Chernobyl, then part of the Soviet Union. The reactor 4 accident released radioactive material into the air, prompting Soviet authorities to evacuate thousands of people from the surrounding area. Homes were abandoned, and often pets were left behind.
In the days after the accident, responders sought out abandoned and stray dogs with the goal of killing them to stop the spread of radiation. However, some seem to have survived.
In the first genetic study of large mammals from the area around Chernobyl, DNA collected from stray dogs living near the plant today reveal that they are descended from dogs that were present at the time of the accident or settled in the area. I made itright after that1Research published March 3 scientific progress, is the first step in a larger project aimed at determining how dogs have adapted to survive in one of the most radioactive places on earth. Researchers hope to use the knowledge gained to better understand the effects of long-term radiation exposure on human genetics and health.
“We have a lot to learn from these animals,” says Elaine Ostrander, a geneticist at the National Institutes of Health in Bethesda, Maryland, and co-author of the study. “This is a great opportunity to see what happens when generations of large mammals live in a hostile environment.”
aftermath
According to the World Health Organization, the direct consequences of the Chernobyl accident were clear. About 30 people who worked at the power plant and firefighters who were present after the disaster died of radiation poisoning within months of the catastrophe. And in the surrounding areas, the pine trees died and many insect species disappeared, unable to survive in the radioactive soil.
What is less clear is how low levels of residual radioactivity from the disaster affect the flora and fauna around Chernobyl today.Several studies have reported unusually high genetic mutation rates in swallows2 Drosophila3 Located near the reactor, he is now buried in an iron and concrete sarcophagus.
However, the health effects of low-level radiation are still hotly debated. David Brenner, a radiation biophysicist at Columbia University in New York, USA, says this is because there is a risk of exposure to low doses of radiation in all situations, including certain medical scans and working at nuclear power plants. said to be important. research. Understanding the effects of this type of exposure is very difficult, but it is very important to do so.
This motivated co-author Timothy Mousseau, an evolutionary ecologist at Columbia’s University of South Carolina. Volunteered to provide veterinary care to hundreds of stray dogs in a 2,600 square kilometer exclusion zone.
During the course of a three-year trip to the region, Mousseau and his colleagues found that about 300 animals living around the power plant and the largely deserted city of Chernobyl were rescued after volunteers tranquilized them with tranquilizer darts. A blood sample was collected from the dog.
A DNA analysis of the dogs revealed they were not new to the region. By comparing this dog’s genetic profile with that of other free-roaming dogs in Eastern Europe, the research team found that dogs (some of which are related to shepherd breeds) found near power plants ) were isolated from other dog populations. decades. And the researchers found that most of these animals didn’t travel far, despite Soviet concerns in the 1980s that dogs would roam and spread radioactive material. over there.
Radioactive legacy
Ostrander said the dogs’ continued presence in the area indicates that they were able to survive and reproduce even when living near the reactor. In the 1986 accident, the deadly radioactive isotope Cesium-137 was deposited at levels 10 to 400 times higher near the power plant than in the city of Chernobyl, just 15 kilometers away.
Dog DNA samples are “incredibly valuable,” Ostrander says, because dogs tend to share much of the same space and diet as humans. “Never before have we had the opportunity to do this work with animals that reflect us, not just dogs.”
But it won’t be easy to pinpoint which genetic changes in dogs are caused by radiation and which are caused by other factors, such as inbreeding or non-radioactive contaminants, warns Brenner. While recognizing the challenges, the researchers believe that detailed knowledge of the ancestry of these dogs, as well as the levels of radiation to which different dogs have been historically exposed, “makes ideal focus groups for future research.” It claims to provide
Meanwhile, Mousseau plans another sampling trip in June. The ongoing war in Ukraine has not stopped the group’s research. But with fewer tourists visiting and leaving leftover food, the Chernobyl dogs are struggling. As such, the team is working with non-governmental organizations to provide food for stray dogs to protect the survival of Chernobyl’s dogs and their radioactive legacy in times of crop failure to come.
This article is reproduced with permission and was first published on March 3, 2023.
