For decades, one of the great unknowns of science after nuclear accidents like Chernobyl has been whether prolonged exposure to radiation leaves a genetic mark that can be passed on to offspring. And although until now I had not found anything relevant, advances in different genomics have begun to shed light on the fact that it is not as harmless as we thought for the different generations that are passing.
New evidence. This is precisely what a team from the University of Bonn has pointed out when publishing an article in which they point out that they have found evidence of a “mutational signature” that passes between different generations in the children of men exposed to radiation after the Chernobyl disaster.
How it was done. To reach this conclusion, the researchers analyzed the complete genomes of different groups to search for genetic material. Here, sequencing data from 130 children of Chernobyl liquidators, who received radiation exposure of up to 4080 mGy, were reanalyzed.
Additionally, 110 children of former German military radar operators exposed to radiation up to 353 mGy were recruited. In order to compare the data, the control was a group of 1,275 children from families that did not have exposure to ionizing radiation.
What was wanted? The easy thing here could be to look for generic mutations that are ‘common’, but the team focused on the mutations de novo grouped. These are nothing more than multiple new mutations in a very short segment of DNA, specifically within a range of 20 base pairs.
The results. What they found here was that the rate of these clustered mutations is significantly higher in children of parents who have been exposed to radiation. Specifically, in the group of people from Chernobyl a rate of 2.65 mutations per offspring was observed and in the group of radar operators (who received less radiation) the average drops to 1.48 grouped mutations.
In the control group, that is, those people who had not received any radiation, these mutations were 0.88, which serves as a basis to begin comparing and drawing conclusions.
Interpretation. With all this data, the researchers point out that the number of these mutations increased proportionally to the radiation dose to which the father had been exposed. And to know why, we have to look at the reactive oxygen species (ROS) that are generated due to this radiation and that induce breaks in the DNA chain of humans.
This is fundamental, because when this damage affects the germ cells in the sperm and the repair mechanisms are activated, different errors occur that accumulate mutations that end up being transmitted to the next generation.
Its consequences. The fact of having a mutation in your DNA due to radiation does not mean that you will have offspring with three eyes, and here science indicates that the probability of these alterations triggering a genetic disease in your children is minimal. In fact, science points to a much more everyday risk factor such as the father’s age, since paternal aging naturally adds between 1 and 2 mutations. de novo isolated for each year of age at conception.
Images | Jorge Fernandez Salas Dasha Urvachova
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