The former commander of the ISS crew, Scott Kelly is no longer the complete twin of his brother Mark Kelly due to genetic changes, reports LiveScience. As the project manager, NASA Twins Study Christopher Mason, when Scott Kelly went to space, in his body there was “a whole heap of changes in the work of individual genes,” some of which “disappeared after returning to Earth, but other changes have not gone anywhere, including changes in work of the immune system and retina of the eye “, reports RIA News” . “So many changes indicate that the body literally tried to adapt to a completely new,” strange “habitat,” – said Mason. The Kelly brothers – both astronauts – participated in the NASA experiment, during which physicians tried to assess how life in orbit affects human health. After taking samples of blood and other tissues before and after Scott’s one-year trip to the ISS, NASA physicians compared them to similar samples obtained from Mark. This opened interesting differences that caused life in space. For example, it turned out that the end sections of chromosomes, which protect them from breakages, have become longer in space. This indicates a certain “rejuvenation” of Scott Kelly cells. On the other hand, in the body of the ISS commander, inflammations began to appear more often, and the condition of his bones deteriorated somewhat due to life in weightlessness. As the researchers note, now Scott Kelly can not be considered a full-fledged twin of Mark – about 7% of his genes work quite differently than before flying to the ISS. In addition to the areas of DNA associated with immunity and vision, the work of those genes that are responsible for the formation of bones, a reaction to a lack of oxygen and an excess of carbon dioxide, as well as the repair of mutations, has changed significantly. Scientists noted that some of the genes were “turned off”, while others became more active. As the newspaper VZGLYAD noted in 2015, an experiment on the US segment of the ISS, devoted to the study of the effect of cosmic radiation on human DNA, was developed Chinese scientists .