Worms in Chernobyl are immune to radiation (Picture: Getty)
The discovery of radiation-proof worms in the Chernobyl exclusion zone could help human cancer research.
It was on April 26, 1986 when disaster struck at the nuclear power plant in Chornobyl, the preferred Ukrainian spelling. An explosion in the No 4 reactor and subsequent leak transformed the surrounding area into the most radioactive landscape on Earth.
More than 150,000 people were evacuated, but many animals continue to live in the region, despite the high levels of radiation that persist nearly four decades later.
Last month, researchers discovered wolves living in the 1,000 square-mile exclusion zone in northern Ukraine were evolving anti-cancer genes, enabling them to thrive.
Now, a new study led by researchers at New York University (NYU) has found that exposure to chronic radiation from Chornobyl has not damaged the genomes of microscopic worms living there today.
This doesn’t mean that the region is safe, the scientists caution, but suggests that these worms are exceptionally resilient.
Wolves in Chernobyl are evolving anti-cancer genes (Picture: Getty/iStockphoto)
The finding could offer clues as to why some humans are more susceptible to cancer than others.
‘Chornobyl was a tragedy of incomprehensible scale, but we still don’t have a great grasp on the effects of the disaster on local populations,’ said first author Dr Sophia Tintori, from NYU.
‘Did the sudden environmental shift select for species, or even individuals within a species, that are naturally more resistant to radiation?’
To answer the question, Dr Tintori and her colleagues turned to nematodes, tiny worms with simple genomes and rapid reproduction, which makes them particularly useful for understanding basic biological phenomena.
Worms collected in the Chornobyl Exclusion Zone, as seen under a microscope (Picture: Sophia Tintori/NYU/SWNS)
“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 senior author Matthew Rockman, a professor of biology at NYU.
In collaboration with scientists in Ukraine and US colleagues, Dr Tintori and Professor Rockman visited the Chornobyl Exclusion Zone in 2019 to see if chronic radiation has had a detectable impact on the region’s worms.
With Geiger counters in hand to measure local levels of radiation and personal protective gear to guard against radioactive dust, they gathered worms from samples of soil, rotting fruit, and other organic material.
Worms were collected from locations throughout the zone with different amounts of radiation, ranging from low levels on par with New York City (negligibly radioactive) to high-radiation sites on par with outer space (dangerous for humans, but of unclear if it would be dangerous to worms).
Dr Sophia Tintori collecting samples in the exclusion zone (Picture: Matthew Rockman/NYU/SWNS)
The team focused on the species Oscheius tipulae, which has been used in numerous genetic and evolutionary studies.
They compared the genome sequence of those from Chornobyl with worms from other parts of the world, and were surprised to find that, using several different analyses, they could not detect a signature of radiation damage in the genomes of the worms from Chornobyl.
This means rather than the worms evolving to cope with radiation, as in the case of the wolves, they are already radiation-proof.
The researchers gathered worms from rotting fruit and other organic matter (Picture: Matthew Rockman/NYU/SWNS)
‘This doesn’t mean that Chornobyl is safe,’ said Dr Tintori. ‘It more likely means that nematodes are really resilient animals and can withstand extreme conditions.
‘We also don’t know how long each of the worms we collected was 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.’
Importantly, the study helped identify which species of O tipulae are more susceptible to DNA damage – not those in Ukraine – which could help scientists understand why some humans are more likely to get cancer than others.
‘Now that we know which strains of O tipulae are more sensitive or more tolerant to DNA damage, we can use these strains to study why different individuals are more likely than others to suffer the effects of carcinogens,’ said Dr Tintori.
‘Thinking about how individuals respond differently to DNA-damaging agents in the environment is something that will help us have a clear vision of our own risk factors.’
The study is published in the journal the Proceedings of the National Academy of Sciences.