A tiny insect that lives in a highly radioactive environment Chernobyl In the Exclusion Zone (CEZ), radiation does not appear to cause any harm whatsoever.
Worms collected from the area showed no signs of damage to their genomes, contrary to what would be expected for organisms living in such a dangerous place. The results, published earlier this year, do not suggest that the CEZ is safe, the researchers said. To tellRather, the insects are resilient and can cleverly adapt to conditions that might be inhospitable to other species.
According to a team of biologists led by Sofia Tintori at New York University, this could provide insight into DNA repair mechanisms that could one day be applied to human medicine.
Since the Chernobyl nuclear power plant’s reactor exploded in April 1986, the surrounding area and the Ukrainian city of Pripyat have been strictly off-limits to the public without government permission. Radioactive material released into the environment exposes living organisms to extremely dangerous levels of ionizing radiation, greatly increasing the risk of mutation. cancerand death.
It will take thousands of years toChernobylThe land, spelled “Safe Zone” in Ukrainian, is once again safe for human habitation. Most of us know that and stay away accordingly. But the animals… don’t understand that. They go where they want. And since then, the Exclusion Zone has become a strangely radioactive area, covering 2,600 square kilometers (1,000 square miles). Animal Sanctuary.
Inspection of animals living in this area showed that Clear genetic differences Protecting against animals that cannot survive is important, but there’s still a lot we don’t know about the impacts of disasters on local ecosystems.
“Chernobyl was a tragedy of immeasurable proportions, but we have yet to fully grasp the impact that the disaster had on the local population.” Tintori said at the time.“Did a sudden environmental change select for species, or individuals within species, that were more resistant to ionizing radiation?”
One way to understand this question is to look at nematodes (which live in various habitats, e.g. Other organismsNematodes are surprisingly hardy; Multiple cases of Reawakening of the nematode rear Thousands of years Frozen in permafrost.
They have a simple genome, A short lifeThis means they can survive for multiple generations in a short period of time, making them a good model organism for studying everything from biological development to DNA repair to responses to toxins, which is why Tintori and her colleagues dug in Chernobyl to find these worms. Osius TipraeIt usually lives in the soil.
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Using Geiger counters to measure radiation levels in their surroundings and wearing protective gear to protect themselves from radioactive dust, they collected hundreds of nematodes from rotting fruit, fallen leaves, and soil at the CEZ. The researchers then cultured about 300 of the nematodes in the lab, where they O. tipulae For genome sequence analysis.
These genome sequences were compared with those of five specimens. O. tipulae They come from all over the world, including the Philippines, Germany, the United States, Mauritius and Australia.
The CEZ nematodes were mostly more genetically similar to each other than to other nematodes, and their genetic distances matched the geographic distances across the sample of 20 strains, but they showed no signs of DNA damage due to the radiation environment.
The team carefully analyzed the worm genomes but found no evidence of the large-scale chromosomal rearrangements expected from a mutagenic environment, and no correlation between the mutation rates of the worms and the strength of the ambient radiation in which they lived.
Finally, the researchers tested the descendants of the 20 worm lineages to see how well the populations tolerated DNA damage. Different lineages had different levels of resistance, but again, this did not correlate with the ambient radiation their ancestors were exposed to.
The team concluded that there was no evidence that the CEZ environment had a genetic effect on the genome. O. tipulae.
And what they find could help researchers understand why some people are more susceptible to cancer than others.
“Now we are O. tipulae “If we find strains that are more sensitive or more resistant to DNA damage, we can use these strains to study why different individuals are more susceptible to carcinogens than others.” Tintari says:.
“Considering how individuals respond differently to DNA-damaging agents in the environment can help us get a clearer picture of our own risk factors.”
This study Proceedings of the National Academy of Sciences.
An earlier version of this article was published in March 2024.
