Khaberni - Nearly four decades after the 1986 Chernobyl nuclear reactor disaster, a new study reveals clear evidence of some effects of radiation exposure being passed to the next generation. Researchers observed subtle changes in the DNA of children of individuals exposed to ionizing radiation during the cleanup operations following the explosion.
The study, led by a team from the University of Bonn in Germany and published in the journal Scientific Reports, is among the first to provide direct evidence of what is known as "transgenerational effect" resulting from long-term exposure to low doses of radiation.
Instead of focusing on individual new genetic mutations, the team looked for a specific pattern known as "clustered de novo mutations" (cDNMs), which are two or more mutations located near each other in a child's DNA, but not present in the parents.
This type of mutations is believed to arise from breaks in the DNA strands of the parents due to radiation, then repaired imperfectly, leaving behind a "genetic fingerprint" that can be detected in the offspring.
The study included full-genome sequencing analysis of 130 children of Chernobyl cleanup workers, 110 children of German military radar operators who were likely exposed to low radiation, as well as 1275 children of parents not exposed to radiation as a control group.
The results showed that the average number of clustered mutations was 2.65 mutations per child in the Chernobyl group, compared to 1.48 in the radar operators' group, and only 0.88 in the control group.
Although the researchers noted the possibility of statistical anomalies that might slightly elevate the figures, the difference remained statistically significant even after adjustments. It also turned out that higher radiation doses in the father were associated with an increased number of mutations in the son, reinforcing the hypothesis of a causal relationship.
This is explained by ionizing radiation producing active molecules known as "reactive oxygen species", capable of causing breaks in the DNA, which may leave behind clustered mutations when repaired imperfectly.
Despite proving the existence of a genetic effect, the study carried a reassuring aspect, as no rise in disease rates among the offspring of the radiation-exposed parents was recorded.
The researchers suggest that most of these mutations occur in non-coding regions of the genome, parts that do not directly control protein synthesis, which reduces the likelihood of their health impact.
Even the study indicates that the effect of the father's age at the time of conception, which is known to increase the number of mutations with advancing age, could be greater than the potential impact of the measured radiation here.
The researchers acknowledge some limitations, as they relied on historical estimates of radiation doses, given decades have passed since the incident. Additionally, participation was voluntary, which could open the door for potential selection bias in the participants.
Nevertheless, the results provide new evidence that prolonged exposure to radiation can leave subtle genetic marks extending into the next generation, even if they do not translate into obvious diseases.
The study underscores again the importance of stringent safety measures and precise health monitoring for workers in radiation-exposed environments, especially those who may be exposed to higher or longer-than-safe doses of radiation. After decades from the catastrophe, Chernobyl still reveals its secrets; this time at the level of the genetic code itself.
