No, after a year in space, Scott Kelly has not changed DNA
According to the latest news, NASA astronaut Scott Kelly flew into space, spent a year there - and returned with significant changes in DNA.
• “Cosmos radically changed the astronaut's DNA on the ISS” (“Rossiyskaya Gazeta”)
• "Life in space" radically changed "astronaut DNA" (RIA Science)
• “Space flights are capable of changing human DNA” (Regnum)
… etc.
Some media even reported that as many as 7% of Kelly's genes were “abnormal” after the flight . This statement makes you think, because in humans and chimpanzees, for example, no more than 2% of the genotype differ, and in two random people - no more than 0.1%.
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The news surprised Scott Kelly himself, who learned about the mutations of his body from the article:
"What? My DNA has changed by 7%! Who would have thought? Just found out about it from the article. It must be good! You no longer have to call [Mark Kelly] your identical twin. ”
Unfortunately, in the mentioned articles, as in many others, the results of a study conducted by NASA are misinterpreted. Journalists 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 during which information from a gene is converted into a functional product - RNA or protein. In the process of adaptation to external conditions, a living organism can change its own structure and functionality, controlling the time, place and quantitative characteristics of individual genes.
As often happens, few have read the explanations of geneticists to the published news. For example, a tweet with news of 5200 retweets (interestingly, the author is also a scientist, although in another area), but the answer to this tweet with an explanation of genetics and the actual refutation of this information is only 1 retweet . Here is another proof that fake news spreads in social media faster than real facts (for this topic, see the scientific article "The spread of true and false news online" in Science ).
What do scientists actually study as part of the Twins Study experiment, which involves several research groups? They compare two identical (identical) twins, Scott and Mark Kelly - and try to identify the changes that have occurred in the body of Scott Kelly after a year in space.
Changes in cognitive abilities, work of the immune system and genetics. The results of the scientific research will be published later this year, but for now the reason for the incorrect interpretation of the information was the NASA press release with rather risky wording.
In fact, about 7% of the genes do not change at all, of course. The study says the change in the level of gene expression. Not surprisingly, in microgravity, the body began to adapt. The study revealed which genes specifically changed the degree of expression. Among them are the genes responsible for the immune system, DNA repair and bone growth.
"Seven percent of the genes that changed their expression during space flight still retained the changed functionality after six months on Earth," said Christopher Mason, head of the NASA science experiment. This is the essence of the news, which is set out in a press release. This does not mean at all that “the astronaut's DNA has not returned to its normal state,” as mass media wrote .
Christopher Mason said that this is the first study of this 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 the human body, which was in a stressful situation. For example, the same indicators for climbers or divers. 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 ecological situation. Of course, a year in microgravity with a reduced level of oxygen in the air and an increased level of irradiation led to such changes.
If we talk specifically about mutations in DNA, then each person has such mutations during their lifetime, and there is nothing special about this. No doubt, just because of the increased exposure, Scott Kelly will have a little more such mutations than any other person who has lived the same number of years but has not left the Earth, but there is nothing unexpected about this. Scientists would be much more surprised by the fact if such mutations did not occur or were fewer than on Earth.
At the moment, the most surprising fact among all the data that NASA received from the results of Scott Kelly’s study is that the telomeres at the ends of the chromosomes in the astronaut ’s white blood cells have increased in size. Typically, telomeres shrink with age as cell divisions occur and thus serve as a natural limiter for the duration of the biological life of an organism.
• “Cosmos radically changed the astronaut's DNA on the ISS” (“Rossiyskaya Gazeta”)
• "Life in space" radically changed "astronaut DNA" (RIA Science)
• “Space flights are capable of changing human DNA” (Regnum)
… etc.
Some media even reported that as many as 7% of Kelly's genes were “abnormal” after the flight . This statement makes you think, because in humans and chimpanzees, for example, no more than 2% of the genotype differ, and in two random people - no more than 0.1%.
')
The news surprised Scott Kelly himself, who learned about the mutations of his body from the article:
"What? My DNA has changed by 7%! Who would have thought? Just found out about it from the article. It must be good! You no longer have to call [Mark Kelly] your identical twin. ”
Unfortunately, in the mentioned articles, as in many others, the results of a study conducted by NASA are misinterpreted. Journalists 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 during which information from a gene is converted into a functional product - RNA or protein. In the process of adaptation to external conditions, a living organism can change its own structure and functionality, controlling the time, place and quantitative characteristics of individual genes.
As often happens, few have read the explanations of geneticists to the published news. For example, a tweet with news of 5200 retweets (interestingly, the author is also a scientist, although in another area), but the answer to this tweet with an explanation of genetics and the actual refutation of this information is only 1 retweet . Here is another proof that fake news spreads in social media faster than real facts (for this topic, see the scientific article "The spread of true and false news online" in Science ).
What do scientists actually study as part of the Twins Study experiment, which involves several research groups? They compare two identical (identical) twins, Scott and Mark Kelly - and try to identify the changes that have occurred in the body of Scott Kelly after a year in space.
Changes in cognitive abilities, work of the immune system and genetics. The results of the scientific research will be published later this year, but for now the reason for the incorrect interpretation of the information was the NASA press release with rather risky wording.
In fact, about 7% of the genes do not change at all, of course. The study says the change in the level of gene expression. Not surprisingly, in microgravity, the body began to adapt. The study revealed which genes specifically changed the degree of expression. Among them are the genes responsible for the immune system, DNA repair and bone growth.
"Seven percent of the genes that changed their expression during space flight still retained the changed functionality after six months on Earth," said Christopher Mason, head of the NASA science experiment. This is the essence of the news, which is set out in a press release. This does not mean at all that “the astronaut's DNA has not returned to its normal state,” as mass media wrote .
Christopher Mason said that this is the first study of this 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 the human body, which was in a stressful situation. For example, the same indicators for climbers or divers. 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 ecological situation. Of course, a year in microgravity with a reduced level of oxygen in the air and an increased level of irradiation led to such changes.
If we talk specifically about mutations in DNA, then each person has such mutations during their lifetime, and there is nothing special about this. No doubt, just because of the increased exposure, Scott Kelly will have a little more such mutations than any other person who has lived the same number of years but has not left the Earth, but there is nothing unexpected about this. Scientists would be much more surprised by the fact if such mutations did not occur or were fewer than on Earth.
At the moment, the most surprising fact among all the data that NASA received from the results of Scott Kelly’s study is that the telomeres at the ends of the chromosomes in the astronaut ’s white blood cells have increased in size. Typically, telomeres shrink with age as cell divisions occur and thus serve as a natural limiter for the duration of the biological life of an organism.
Source: https://habr.com/ru/post/410871/
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