On April 26, 1986, it was 1:23 a.m. when an explosion shook the Chernobyl power plant, in what was then a region of the USSR, now Ukrainian. It’s already too late when an employee rushes to press the emergency button. The meltdown of the core of one of the reactors has just triggered the most serious nuclear disaster in history.
At the time, hundreds of thousands of people were working to clean up the radioactive waste and secure the area, they were called “liquidators”. They are exposed to radiation, become ill, and some die. Today, the effects of this radiation are being closely studied on the survivors: by examining the latter’s genes, researchers noticed that certain mutations had been transmitted to their children.
“It is necessary to study these effects in order to design effective preventive measuressays physicist Peter Krawitz, of the University of Bonn in Germany, in a study recently published in the journal Nature. The risk of transmitting radio-induced genetic alterations to the next generation is of particular concern for parents who may have been exposed to higher doses of ionizing radiation and potentially for longer periods than those considered safe.”
How is this possible? Radiation directly attacks our cells via water (we are made up of 70% of it). These water molecules then become hyperaggressive and unstable. To stabilize, they will attach to the DNA, which they will either directly break or damage. Our cells, in panic, will therefore try to repair it, but sometimes by sticking the wrong information in the wrong place. This is called translocation. The consequences are quite simple: either the cell is too damaged and dies, or the translocation develops tumors.
A transmission from one generation to another
But for Peter Krawitz, the problem does not end there. The researcher tried to detect these mutations directly in children. To do this, he isolated the genomes of people who participated in the clean-up of Chernobyl, as well as those of German military radar operators during the Cold War.
By studying genomes for abnormalities, researchers targeted areas of DNA with damage. The descendants of Chernobyl present much more than the others. Most were not serious, but the increase in new mutations was found to be directly linked to the father’s exposure to radiation. In other words, these mutations can be transmitted from one generation to the next. Genetic analysis of descendants confirmed this: mutations are significantly more frequent in children of irradiated parents than in the rest of the population. Invisible even under a microscope, these mutations would have remained undetectable without genomic sequencing.
Despite these hereditary mutations, children do not develop diseases or malformations. This exposure therefore seems to be a less important factor than the age of the parents at the time of conception of the child when it comes to genetic diseases, explains Popular Mechanics.
“This study is the first to demonstrate the existence of a transgenerational effect of prolonged paternal exposure to low doses of ionizing radiation, concludes Peter Krawitz. These results open several promising avenues of research to more precisely characterize the transgenerational signatures of the effect of radiation on the human genome.”
