A population of wild dogs living near the site of the Chernobyl nuclear plant meltdown is giving scientists a glimpse into how long-term radiation exposure affects generations of living beings.
The radiation – still being emitted decades after the 1986 nuclear disaster which saw the Chernobyl Nuclear Reactor explode, sending a massive plume of radiation into the sky – means the area surrounding the plant is essentially uninhabited by humans but is home to hundreds of dogs.
Now scientists believe that radiation may have fundamentally altered the genetics of the strays living within the Chernobyl Exclusion Zone.
That’s according to a new report from the University of South Carolina and the National Human Genome investigating how radiation exposure may have altered animals’ genomes—and even, possibly, sped up evolution.
The study recently published in Science Advances, uncovered that the feral dogs living near the Chernobyl Power Plant showed distinct genetic differences from dogs living only some 10 miles away in Chernobyl City.
‘Do they have mutations that they’ve acquired that allow them to live and breed successfully in this region?’ co-author Elaine Ostrander, a dog genomics expert at the National Human Genome Research Institute said. ‘What challenges do they face and how have they coped genetically?’
Scientists are also looking for other developmental abnormalities, such as tumours, and smaller brain sizes.
Chernobyl Dog Research Initiative
The dogs still living around the Chernobyl Exclusion Zone (CEZ) are likely descendants of pets left behind after residents surrounding the power plant fled the region. At the time it was in the Soviet Union, now it falls within the borders of Ukraine.
The radioactive contamination devastated wildlife populations in the region, but some abandoned animals survived and continued to breed.
Researchers used preserved blood samples collected by the Chernobyl Dog Research Initiative, an organisation that has been providing veterinary care to animals in the area.
Jennifer Betz, the veterinarian who heads the veterinary care program, explains: ‘We capture the dogs, spay/neuter them, vaccinate, microchip, tag them … Then we release them where they came from so they can live out their lives as happy and healthy as they possibly can.’
The dogs cannot be removed from the zone however because, she says, ‘they can carry significant amounts of radioactive contaminants, either in their fur or in their bones.”
Many of the effects the researchers have seen in the dogs and other animals parallel what has been observed in the past with atomic bomb survivors from Japan during World War II, said Tim Mousseau, a professor of biological sciences at the University of South Carolina.
For instance, they have increased rates of cataracts, because the eyes are the first tissues to show signs of chronic exposure to ionizing radiation, Mousseau said.
Although exposure to ionizing radiation is known to elevate genetic mutation rates across various plant and animal species, it is still unclear how larger animals may be impacted at the population level, according to the study.
The unique genetic diversity of these dogs makes them ideal candidates for future studies seeking to understand the long-term genetic health effects of highly radioactive environments on populations of large mammals, especially in understanding the biological underpinnings of human survival in regions of high and continuous environmental assault, the researchers said.
‘It was a dream come true for me to be able to do some really sophisticated, advanced genetics in a way that had never been done before in this setting and on a model organism,’ Mousseau said.
Scientists have been analysing certain animals living within the CEZ for years, including bacteria, rodents, and even birds.
In 2016 an investigation found that Eastern tree frogs, which are usually a green colour, were more commonly black within the CEZ. The biologists theorise that the frogs experienced a mutation in melanin—pigments responsible for skin colour—that helped ionise the surrounding radiation.
Researchers say the study has shown that an area that should be a wasteland has become an unparalleled scientific opportunity to understand radiation and its impact on natural evolution.
Researchers intends to carry out more studies on the canines, in the hope of revealing genetic mutations associated with surviving in harsh, radioactive environments. Future insights into these dogs could help protect people against radiation exposure or lead to cancer treatments.
