Chernobyl dogs' rapid evolution: Adapting to radiation's legacy
The quadrupeds currently residing in the exclusion zone in Chernobyl are descendants of domesticated animals abandoned by residents fleeing the nuclear disaster in 1986. It appears they have undergone rapid genetic changes.
After the nuclear catastrophe in Chernobyl on 26 April 1986, about 120,000 people from nearby towns, including Prypiat, had to leave their homes. Among them were many dogs, which, against all odds, created a strong population, still living in the highly contaminated radioactive land.
According to the latest data, as many as 800 semi-wild dogs may be living in the area surrounding Chernobyl. These animals are partially reliant on humans because scientists and local workers feed them, and veterinarians sometimes update their vaccinations and treat their medical issues. It now seems that the Chernobyl dogs have evolved over the 40 years since the disaster. Have they become a new separate species?
Dogs living closest to the power plant explosion have different DNA
In an article published by the journal Science Advances, scientists genetically tested 302 dogs residing at the power plant and within a distance of about 15 kilometres to 45 kilometres from the explosion site. These dogs live in the Chernobyl Exclusion Zone, spanning an area of about 2,600 square kilometres, which was enclosed to prevent radioactivity. After analysing dog blood samples, they noticed that those closest to the explosion site have DNA quite different from dogs in the rest of the world.
According to scientists, this is the result of exposure to ionising radiation over multiple generations. The research identified 15 complex family structures of Chernobyl dogs that differed from other dogs globally, even though these dogs move across various areas and freely interbreed. The research team now wants to verify if the genetic differences affect the animals' health, appearance, and behaviour. Elaine Ostrander, author of the study and a geneticist at the American National Human Genome Research Institute (NIH), emphasised that one goal is to discover DNA variants acquired since the accident that help them survive in high radiation conditions.
Not only dogs have evolved
It is still unclear how these genetic differences affect the health and traits of the dogs. However, they are not the only species that seems to have evolved due to the disaster. Current studies on the genetics of wolves from this area indicate they have developed cancer resistance. Another study noted that tree frogs in the exclusion zone are darker than those living outside it, which may result from a higher level of melanin that reduces the negative impact of radiation.
Why is this happening? Although the study itself does not explain why Chernobyl dogs are genetically different from their relatives in less radioactive regions, there are many ways radiation can affect animal populations. As explained in the research, radiation can cause mutations that contribute to genetic diversity passed down from generation to generation. Another hypothesis is the death of individuals unable to cope with the effects of radiation, resulting in a population better adapted to new conditions and a reduction in genetic diversity.
One thing is certain: the genetic changes observed in Chernobyl dogs demonstrate surprisingly rapid evolutionary processes in populations experiencing environmental changes, leaving much more to explore.
