The media lied again
No, after a year in space, Scott Kelly's DNA hasn't changed
Anatoly Alizar, Geektimes
According to the latest news, NASA astronaut Scott Kelly flew into space, spent a year there – and returned with significant changes in DNA.
"Space has radically changed the DNA of an astronaut on the ISS" (Rossiyskaya Gazeta)
"Life in space"radically changed the "astronaut's DNA" (RIA Nauka)
"Space flights can change human DNA" (Regnum)
etc.
Some media even reported that as much as 7% of Kelly's genes turned out to be "abnormal" after the flight. This statement makes you think, because a human and a chimpanzee, for example, differ by no more than 2% of the genotype, and two random people – no more than 0.1%.
The news surprised Scott Kelly himself, who learned about his body's mutations from the article:
"What? My DNA has changed by 7%! Who would have thought? I just found out about it from an article. That's probably a good thing! No more having to call [Mark Kelly] your identical twin."
Unfortunately, in these articles, as in many others, the results of the research conducted by NASA are misinterpreted. Journalists have confused two different concepts – changes in the sequence of genes and changes in the level of their expression, explains the popular science publication National Geographic.
Gene expression is a process in which information from a gene is transformed into a functional product – RNA or protein. In the process of adaptation to external conditions, a living organism is able to change its own structure and functionality, controlling the time, place and quantitative characteristics of individual genes
As often happens, few people have read the explanations of geneticists to the published news. For example, a tweet with the news has 5200 retweets (interestingly, the author is also a scientist, although in a different field), but the response to this tweet with an explanation of the geneticist and the actual refutation of this information has only 1 retweet. Here is another proof that fake news spreads on social media faster than real facts (on this topic, see the scientific article "The spread of true and false news online" in Science).
What are scientists actually studying in the framework of the Twins Study experiment, in which several research groups participate? They compare two identical (identical) twins Scott and Mark Kelly – and try to determine the changes that occurred in Scott Kelly's body after a year in space.
Changes in cognitive abilities, immune system functioning and genetics. The results of the scientific research themselves will be published later this year, but for now, the basis for incorrect interpretation of the information was a NASA press release with rather risky formulations.
In fact, of course, there is no question of any change in 7% of genes. The study talks about a change in the level of gene expression. It is not surprising that in the conditions of microgravity, the body began to adapt. The study revealed which specific genes changed the degree of expression. Among them are genes responsible for the immune system, DNA repair and bone growth.
"Seven percent of the genes that changed their expression during spaceflight still retained their altered functionality after six months on Earth," said Christopher Mason, head of NASA's science experiment. This is the essence of the news, which is set out in the press release. This does not mean at all that "the astronaut's DNA has not returned to normal," as the mass media wrote.
Christopher Mason said that this is the first study of its kind, so it is difficult to predict what results will be obtained next. But he added that such a change in the level of gene expression is normal for a human body that is in a stressful situation. For example, climbers or divers have the same indicators. And in general, significant changes in the level of gene expression occur in all unusual situations: when a person is ill or has fallen into an unfavorable environmental situation. Of course, a year in microgravity with a reduced level of oxygen in the air and an increased level of radiation has led to such changes.
If we talk specifically about mutations in DNA, then in every person such mutations occur during life, and there is nothing special about it. No doubt, just because of the increased radiation exposure, Scott Kelly will have slightly more such mutations than any other person who has lived the same number of years but has not left Earth, but there is nothing unexpected about this. Scientists would be much more surprised by the fact if such mutations did not occur or there were fewer of them than on Earth.
At the moment, the most surprising fact among all the data that NASA has received from the results of the study of Scott Kelly's body is that the telomeres at the ends of chromosomes in the astronaut's white blood cells have increased in size. Usually telomeres shrink with age as cells divide – and thus serve as a natural limiter for the duration of the biological life of the organism.
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