Genetic mystery: Chernobyl dogs defy mutation theory
The causes of this phenomenon have long been a mystery, and newly conducted research complicates the situation even further, suggesting that increased mutation did not have a significant impact on this rapid evolution.
The quadrupeds currently residing in the exclusion zone in Chernobyl are descendants of domestic animals left behind by residents fleeing the nuclear disaster in 1986. As it turns out, in the shadow of the greatest nuclear disaster, the dog population in Chernobyl, Ukraine, has become genetically distinct from other dogs in the rest of the world.
Up to 800 semi-wild dogs live in Chernobyl and its vicinity
After the nuclear disaster in Chernobyl on April 26, 1986, about 120,000 people from nearby towns, including Pripyat, had to leave their homes. Many dogs ended up in this area, which, against all odds, formed a strong population that continues to live in the high contamination of radioactive soil. As previously reported, according to the latest data, up to 800 semi-wild dogs live in the area surrounding Chernobyl and have undergone evolution over the 37 years since the disaster.
Have they become a new separate species? Their DNA has changed enough that they can be identified based solely on their genetic profile. Scientists believe this reflects the long-term impact of environmental pollution. Researchers believe it is the result of these dogs being exposed to ionizing radiation for many generations.
The changed DNA of Chernobyl's dogs is not due to mutation
The latest research, just published in the scientific journal "PLOS One", suggests that the mutation caused by the disaster is not the reason for the genetic differentiation between the two studied populations of dogs in Chernobyl. Scientists examined two populations of quadrupeds: one from the wider area of the former nuclear power plant, and the other from Chernobyl itself.
"With this study, we do not find evidence of an increased mutation rate for the Nuclear Power Plant population of dogs through chromosomal aberrations, increased microsatellite diversity, or an increase of more recently derived alleles," the seven researchers wrote in their published study. They add that the ultimate cause of this genetic diversity has not yet been identified.
These studies confirm one thing – earlier findings remain true that the freely living dogs within the plant's area are genetically different from those residing 16 kilometres away in Chernobyl, as well as from the dog populations outside the exclusion zone.
The actual cause of this diversity remains unknown, although the team has found some evidence suggesting that directional selection may play an important role in the entire process. Further studies may confirm this. Scientists point out that they could serve as effective indicators of human health in the face of toxic environmental exposures.
It's not only dogs that 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 seem to have evolved due to the disaster. Current genetic research on wolves in this area indicates they have developed resistance to cancer. 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 harmful effects of radiation.
It's not only dogs affected by the harsh environment of Chernobyl. For example, sparrows in the exclusion zone have specific gut microbiomes, while tree frogs have changed colour, and wolves have developed an altered immune system.
