Tiny Worms Living Near Chernobyl Have Evolved a Remarkable New Talent

Microscopic worms that live their lives in the highly radioactive environment of the Chernobyl Exclusion Zone (CEZ) appear to do so completely free of radiation damage.

Nematodes collected from the area have shown no sign of damage to their genomes, contrary to what might be expected for organisms living in such a dangerous place. The finding doesn't suggest the CEZ is safe, the researchers say, but rather the worms are resilient and able to adroitly adapt to conditions that might be inhospitable to other species.

This, says a team of biologists led by Sophia Tintori of New York University, could offer some insights into DNA repair mechanisms that could one day be adapted for use in human medicine.

Since the explosion of a reactor at the Chernobyl Nuclear Power Plant in April 1986, the area around it and the nearby town of Pripyat in Ukraine have been strictly off-limits to anybody without government approval. The radioactive materials deposited into the environment expose organisms to extremely unsafe levels of ionizing radiation, greatly enhancing the risk of mutation, cancer, and death.

It's going to be thousands of years before 'Chornobyl', as it is spelt in Ukraine, is safe for human habitation again. Most of us know that and steer clear accordingly. But animals … well, they don't understand to stay away. They go where they want, and the exclusion zone has since become a strange sort of radioactive, 2,600-square kilometer (1,000 square mile) animal sanctuary.

Tests of animals that live in the region have shown clear genetic differences from animals that don't. But there's still a lot we don't know about the effects of the disaster on the local ecosystems.

"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," Tintori says. "Did the sudden environmental shift select for species, or even individuals within a species, that are naturally more resistant to ionizing radiation?"

One way to gain insights into this question is to look at nematodes – microscopic roundworms that live in a range of habitats (including the bodies of other organisms). Nematodes can be remarkably hardy; there have been multiple cases of nematodes reawakening after thousands of years frozen in permafrost.

They have simple genomes, and live short lives, which means multiple generations can be studied in a short space of time. This makes them excellent model organisms for studying a range of things, from biological development, to DNA repair and toxin response. This is why Tintori and her colleagues went digging in Chornobyl to find nematodes of the species Oschieus tipulae, which typically lives in soil.