The Chernobyl Legacy

The Chernobyl explosion is the worst nuclear accident on record. The two massive explosions blew four hundred times the amount of radiation from the Hiroshima bomb into the air. Its impact is still being uncovered.

A new study sequenced the entire genomes of one hundred thirty children and their parents who were brought in to clean up the disaster or were evacuees from areas near the plant. Children born forty-six or more weeks after the accident were included.

They found that nearly all the children's inherited genetic variation is also present in the DNA of each parent. Some of the variations are from changes in either the sperm or the egg which are called de novo mutations or DNMs. Normally, between fifty to one hundred DNMs arise per individual per generation. Surprisingly, the radiation exposure did not raise these children's DNMs.

Exposure to radioactive iodine can also raise a person's risk for thyroid cancer, so a study looked at thyroid tumors from over three hundred people exposed to radiation at Chernobyl and compared them with those born near there later.

Those exposed did have more breaks in both strands of DNA and the more radiation a person was exposed to and the younger they were, the more double stand DNA breaks they accumulated.

So, there's good and bad news. Chernobyl did not cause more mutations to be passed down to the next generation, but it did raise the number of thyroid cancers. Over three decades have passed and yet we will continue to learn from the fallout.