Chernobyl nuclear disaster caused DNA mutation in children, study finds
What's the story
A study has found genetic changes in the children of people exposed to radiation during the 1986 Chernobyl disaster near Pripyat in Ukraine. This is the first time a link between radiation exposure and specific mutation patterns in offspring has been established. Researchers were able to identify such DNA damage after changing their search strategy. Previous studies have looked for genetic damage handed down from parent to child but found no evidence in the case of Chernobyl victims.
Study
Study led by a team from University of Bonn
Researchers led by a team from the University of Bonn in Germany employed a different approach. The research focused on "clustered de novo mutations" (cDNMs), which are groups of mutations that appear close together in a child's DNA but are absent in their parents. These mutations result from breaks in the parental DNA caused by radiation exposure.
Research findings
Genetic changes observed in children of exposed individuals
The study, published in Scientific Reports, sequenced the genomes of three groups: 130 children of Chernobyl cleanup workers and residents, 110 children of German military radar operators exposed to stray radiation, and 1,275 unexposed individuals. On average, Chernobyl cleanup workers' children had 2.65 cDNM clusters each, while those of radar operators had 1.48 clusters and the unexposed group had only 0.88 clusters.
Genetic implications
Ionizing radiation and its impact on DNA
Ionizing radiation creates reactive oxygen species that can break DNA strands in developing sperm cells. When these breaks are repaired, small groups of mutations may remain and become part of a child's genome. The study found a dose relationship between parental exposure and mutation clusters in children, with estimated exposure averaging about 365 milligrays, enough to leave a detectable genetic trace but below levels associated with acute radiation sickness.
Mutation location
Mutations mostly in non-coding regions
Most mutations were found in non-coding regions of the genome, which do not produce proteins. This is significant, as harmful genetic diseases usually involve coding regions. Despite the inherited biological signature from the Chernobyl disaster, no higher disease risk was found among the studied children. The study concluded that "the likelihood that a disease occurring in the offspring of exposed parents is triggered by a cDNM is minimal."