Now, 35 years after the devastating Chernobyl nuclear accident, scientists with today's advanced methods have been able to reveal more details about the genetic effects of the ionizing radiation to which people living or working nearby were exposed. 

The results are presented in two studies published in the scientific journal Science. 

- It is well-conducted studies and merited researchers who have carried them out.

These are important works that give us more details about the hereditary effects of radiation and about cancer induced by radiation, says Mats Harms-Ringdahl, professor emeritus in radiation biology at Stockholm University.

Children of clearing workers

In one study, the researchers examined 130 children born between 1987 and 2002 and their parents.

Many of the children had parents who participated in the clearing work among the radioactive remains in the ruins after the nuclear power reactor.

The researchers studied the entire genome of the children and parents but mainly examined so-called de novo mutations.

These are genetic changes that have occurred in a child as a result of a mutation in one of the parents' gametes.

Minimal impact on subsequent generations

Previous animal studies have suggested that children of parents exposed to ionizing radiation could carry many more such mutations than usual. 

But the results show that the children had no surplus of these and the researchers conclude that the radiation during and after the Chernobyl accident had a minimal health impact on subsequent generations. 

According to Mats Harms-Ringdahl, the study confirms the epidemiological analyzes carried out on the survivors of the atomic bombs in Hiroshima and Nagasaki, which did not show any hereditary effects of the radiation. 

- The study is based on extensive analyzes of the genome of children of parents who were exposed in connection with the nuclear accident in Chernobyl.

With completely different technology and different exposure scenarios, the study is an important confirmation that the radiation has a very limited effect on humans in terms of hereditary effects, he says.  

Thyroid cancer increased

However, several children already born at the time of the accident were affected.

It has been seen that they were at a higher risk of developing thyroid cancer later in life. 

In the second study, the researchers investigated whether it is possible to distinguish a thyroid cancer tumor that has arisen from radiation from a tumor that has arisen from other causes. 

Therefore, 440 people diagnosed with thyroid cancer were studied in Ukraine, of which 359 were exposed to the radiation and 81 were not. 

No marker for radiation-induced tumors

The researchers were unable to find any way to distinguish tumors arising from radiation from other tumors.

However, they saw a dose-dependent carcinogenic effect of radiation.

This was primarily due to the occurrence of double-strand breaks, a complicated damage to the DNA.

- It is already well known that double-strand breaks caused by ionized radiation are difficult to repair and can cause mutations that lead to the emergence of cancer cells.

This study adds detailed genetic analyzes of tumors that have arisen after radiation and helps to increase the understanding of the carcinogenic process, says Mats Harms-Ringdahl.

Studies such as these two are important for basic research but also because they provide knowledge that is valuable for the scientific basis on which risk assessments regarding the effects of radiation on humans are based.

Play the clip to see what it looked like during the clearing work in Chernobyl in 1986. Some of the children studied are children of clearing workers.