Researchers report measurable genetic changes linked to parental radiation exposure, though overall disease risk remains low.
By yourNEWS Media Newsroom
Nearly 40 years after the Chernobyl nuclear disaster, new research indicates that children born to men exposed to radiation during cleanup operations carry a higher number of specific DNA mutation clusters, according to a study published in Scientific Reports.
Scientists from the University of Bonn examined whether radiation exposure experienced by workers at the Chernobyl nuclear power plant accident site resulted in inherited genetic changes in their children. While earlier research had left the question unresolved, the new findings suggest a measurable increase in what are known as “clustered de novo mutations,” or cDNMs, among the offspring of exposed fathers.
Rather than analyzing all new mutations, researchers focused on cDNMs—instances where two or more new mutations appear close together on a DNA strand. Such clustering indicates that DNA may have been broken and imperfectly repaired.
The team sequenced the genomes of 130 children whose fathers had either lived in Pripyat at the time of the 1986 explosion or worked as “liquidators” responsible for guarding and cleaning the site. For comparison, researchers also studied 110 children of German military radar operators exposed to stray radiation and 1,275 individuals with no known parental radiation exposure.
On average, children of Chernobyl cleanup workers had 2.65 clustered mutations. Children of radar operators averaged 1.48, while those in the non-exposed group averaged 0.88 per person.
The study also identified a relationship between the estimated radiation dose received by fathers and the number of clustered mutations observed in their children. Higher exposure levels corresponded with higher mutation counts.
In their paper, available here, the researchers wrote: “We found a significant increase in the cDNM count in offspring of irradiated parents, and a potential association between the dose estimations and the number of cDNMs in the respective offspring.”
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They added, “The present study is the first to provide evidence for the existence of a transgenerational effect of prolonged paternal exposure to low–dose [ionising radiation] IR on the human genome.”
The researchers caution that the sample size was relatively limited and that statistical noise may slightly inflate the figures, though they reported that the findings remained significant after adjustments.
Scientists believe that ionizing radiation exposure generated reactive oxygen species in the fathers’ bodies—unstable oxygen-containing molecules capable of damaging DNA. When sperm cells were affected, clusters of mutations formed and were later transmitted to offspring.
Despite the higher mutation counts, researchers found no evidence that the children face increased health risks. The mutations were located in non-coding regions of DNA, which do not produce proteins and are less likely to affect biological function. The study concluded that the children were not at greater risk of disease than the general population.
For context, the study notes that paternal age at conception is associated with a higher number of inherited mutations than the radiation exposure levels observed in this cohort. The estimated radiation exposure among the Chernobyl workers averaged approximately 365 milligrays, compared to NASA’s career-long astronaut exposure limit of 600 milligrays.
The findings contribute to ongoing research into the long-term genetic consequences of radiation exposure, while suggesting that, in this case, the observed mutations have limited clinical impact.
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