From black frogs to a new species of dog, radiation exposure has forced many animals living near Chernobyl to mutate.
But a new study shows that not all animals in the exclusion zone have responded this way.
Worms living near Chernboyl (or Chornobyl in the preferred Ukrainian spelling) have developed a new “superpower”: they appear to be immune to radiation.
“Chornobyl was a tragedy of incomprehensible scale, but we still do not have a clear idea of ​​the effects of the disaster on local populations,” said Dr. Sophia Tintor, lead author of the study.
‘Did the sudden environmental change select for species, or even individuals within a species, that are naturally more resistant to ionizing radiation?’
Worms living near Chernboyl have developed a new “superpower”: they appear to be immune to radiation
The 1986 disaster at the Chernobyl nuclear power plant transformed the surrounding area into the most radioactive landscape on Earth.
The 1986 disaster at the Chernobyl nuclear power plant transformed the surrounding area into the most radioactive landscape on Earth.
Humans were evacuated, but many plants and animals continue to live in the region, despite high levels of radiation that persist almost four decades later.
In recent years, researchers have discovered that some animals living in the Chernobyl exclusion zone (the region of northern Ukraine within a 30-kilometer radius around the power plant) are physically and genetically different from their counterparts in elsewhere, raising questions about the impact of chronic diseases. Radiation in DNA.
In the new study, researchers visited Chernobyl to study nematodes, small worms with simple genomes and rapid reproduction, making them particularly useful for understanding basic biological phenomena.
“These worms live everywhere and they live quickly, so they go through dozens of generations of evolution while a typical vertebrate is still putting on its shoes,” said Matthew Rockman, a biology professor at New York University and senior author of the paper. study.
With Geiger counters in hand to measure local radiation levels and personal protective equipment to protect against radioactive dust, they collected worms from soil samples, rotting fruit and other organic materials.
The worms were collected in locations across the area with varying amounts of radiation, from low levels on par with New York City to sites with high radiation on par with outer space.
Back in the NYU lab, researchers studied the worms, part of which involved freezing them.
The worms were collected in locations across the area with varying amounts of radiation, from low levels on par with New York City to sites with high radiation on par with outer space.
“We can cryopreserve worms and then thaw them for later study,” Professor Rockman explained.
“That means we can stop evolution in the laboratory, something impossible with most other animal models, and very valuable when we want to compare animals that have experienced different evolutionary histories.”
The researchers were surprised to discover that they could not detect any signs of radiation damage in the genomes of the Chernobyl worms.
“This does not mean that Chernobyl is safe; rather it means that nematodes are really hardy animals and can withstand extreme conditions,” Dr. Tintori said.
“We also don’t know how long each of the worms we collected spent in the Zone, so we can’t be sure exactly what level of exposure each worm and its ancestors received over the past four decades.”
Wondering whether the lack of genetic signature was because worms living in Chernobyl are unusually efficient at protecting or repairing their DNA, the researchers designed a system to compare how quickly worm populations grow and used it to measure sensitivity of the offspring of each of the 20 genetically distinct worms suffered different types of DNA damage.
While the worm lineages were different from each other in how well they tolerated DNA damage, these differences did not correspond to the radiation levels at each collection site.
The 1986 disaster at the Chernobyl nuclear power plant transformed the surrounding area into the most radioactive landscape on Earth.
Their findings suggest that the Chernobyl worms are not necessarily more tolerant of radiation and that the radioactive landscape has not forced them to evolve.
The results give researchers clues about how DNA repair may vary from one individual to another.
And, despite the genetic simplicity of nematodes, the findings could lead to a better understanding of natural variation in humans.
“Now that we know which strains of O. tipulae are more sensitive or more tolerant to DNA damage, we can use them to study why different individuals are more likely than others to suffer the effects of carcinogens,” said Dr. Tintori .
How different individuals of a species respond to DNA damage is a priority for cancer researchers seeking to understand why some humans with a genetic predisposition to cancer develop the disease, while others do not.
“Thinking about how individuals respond differently to environmental agents that damage DNA is something that will help us get a clear picture of our own risk factors,” Dr. Tintori added.
WHAT IS THE CHERNOBYL EXCLUSION ZONE?
In 1986, an explosion at the Chernobyl power plant in the former Soviet city of Pripyat leaked radioactive material into the environment.
The explosion was due to a fire in one of the nuclear reactors, so the surrounding area was evacuated.
Around 116,000 people were permanently evacuated from the exclusion zone around the power station, leaving towns and cities in ruins.
While radiation levels in the region are still considered too high for humans to return, wildlife has returned to the 1,600-square-mile (4,300-square-kilometer) Chernobyl Exclusion Zone (CZE) and is thriving.
While radiation levels in the region are still considered too high for humans to return, animals such as wolves (pictured) have returned to the area and are thriving.
Many argue that the region should be handed over to the animals that have settled in the area, creating a radioactive protected wildlife reserve.
Studies of animals and plants in the area around Chernobyl are now providing clues about what the world would be like if humans suddenly disappeared.
Scientists are monitoring the health of plants and animals in the exclusion area to see how they react to chronic radiation exposure.
Camera traps set up by researchers have captured an impressive variety of local wildlife, including wolves, lynx, mice, wild boar, deer, horses and many others, as they roam the area.
It shows that three decades after the disaster, the area is far from a wasteland. Instead, life thrives there.