Dogs have made the radioactive remains of the Chernobyl Nuclear Power Plant their home for generations. Scientists have conducted the first genetic analysis of these dogs and found that those living in the power plant industrial area have genetic variations that set them apart from dogs living further away.
|Scientists have completed the first genetic analysis of Chernobyl's dogs. This pack of roaming dogs lives in the former power plant's industrial areas. T. MOUSSEAU
The researchers were able to differentiate between dog populations but did not definitively attribute any genetic differences to radiation exposure. However, these findings, reported in Science Advances on March 3, could be a starting point for future studies that explore the ways in which radioactive environments affect animal genomes.
According to Timothy Mousseau, an evolutionary ecologist at the University of South Carolina in Columbia, the discoveries made about these Chernobyl dogs could have implications beyond understanding the effects of the disaster on animals. Mousseau suggests that the research could also be useful for studying human exposures to radiation in the future, including those related to nuclear disasters and space travel.
Mousseau has visited Chornobyl many times since his first trip in 1999, but it was not until 2017, on a trip with the Clean Futures Fund+, an organization that provides veterinary care to the animals, that he encountered the area's semi-feral dogs. It remains unclear how these dogs survived the nuclear accident. In 1986, an explosion at one of the power plant's reactors resulted in a catastrophic event that scattered enormous quantities of radioactive isotopes into the atmosphere. The resulting radioactive cloud settled mainly in the nearby region, which is now known as the Chornobyl Exclusion Zone.
Since the disaster, dogs have been living in the area, supported by both Chernobyl cleanup workers and tourists. Approximately 250 strays resided within the power plant vicinity, near spent fuel-processing facilities and in the shadow of the ruined reactor. Several hundred more roam further out in the exclusion zone, which is roughly the size of Yosemite National Park.
On Timothy Mousseau's many visits to Chernobyl, his team gathered blood samples from the resident dogs to conduct DNA analysis, allowing them to map out the complex family structures of these animals. Elaine Ostrander, a geneticist at the National Human Genome Research Institute in Bethesda, Md., notes that the canine packs are not a random collection of feral dogs. Instead, there are distinct dog families breeding, living, and surviving in the power plant area. This was a surprising discovery, she notes, given the challenging living conditions in the area.
The research team found that dogs in the exclusion zone share ancestry with German shepherds and other shepherd breeds, much like other free-breeding dogs found in Eastern Europe. The study also found that dogs living in the power plant area have genetic differences from dogs living in Chernobyl City, which is about 15 kilometers away. However, the researchers cannot say for certain whether radiation exposure caused these differences. Ostrander suggests that the dogs may be genetically unique because they live in a relatively isolated area.
Jim Smith, an environmental scientist at the University of Portsmouth in England who has studied this field for decades, finds the study's findings unsurprising. He expresses concern that people may wrongly assume that radiation exposure caused these genetic differences, as there is currently no evidence to support this hypothesis.
For decades, scientists have been trying to determine how radiation exposure at Chernobyl has affected the wildlife in the area. According to Timothy Mousseau, the consequences for birds, rodents, bacteria, and plants have been studied. His team has discovered that animals have elevated mutation rates, shortened lifespans, and early-onset cataracts due to radiation exposure. However, Jim Smith notes that it is challenging to distinguish the effects of low-dose radiation from other factors in the environment, and animals can sometimes benefit from human evacuation.
Elaine Ostrander explains that her team is currently investigating how radiation damage may be accumulating in the genomes of the dogs. Bridgett vonHoldt, an evolutionary geneticist at Princeton University who was not involved in the study, notes that understanding the dogs' genetic backgrounds will help to identify any genetic markers of radiation exposure.