Astronaut's DNA no longer identical to twin after year in space

Mark and Scott Kelly. 

Mark and Scott Kelly. NASA

Mike Kelly, an astronaut who broke the record for the most consecutive days spent in space, has changes in his gene expression that his identical twin brother Scott Kelly, also an astronaut, does not have, according to the report. It was a ground-breaking study comparing what happened to astronaut Scott Kelly, in space, to his identical twin brother, Mark, who remained on Earth. Kelly himself even tweeted about the idea that he's no longer identical twins with his brother and fellow astronaut Mark Kelly.

Some of the genes that seem to have changed permanently involved DNA fix, bone formation and how the cells use oxygen. These are directly related to immune system, DNA fix, bone formation, and more. Last year, NASA published its first round of preliminary results at the 2017 Investigator's Workshop. The 2018 IWS is Act 2, where findings from 2017 were corroborated, with some additions. "NASA and the other researchers collaborating on these studies expect to announce more comprehensive results on the twins studies this summer". What changed was the way his DNA was transcribed and translated into functional products; the study of such shifts is called epigenetics.

But you wouldn't know that from reading some of the coverage the January announcement inexplicably spawned this week - articles claiming that the mission activated Kelly's "space genes", that seven per cent of his genes didn't return to normal post-spaceflight, and that he and Mark are no longer identical twins.

The agency emphasized the change in Scott Kelly, was "very minimal".

Yet as genes turn on and off, change in the function of cells may occur.

Some changes included "cell-free" DNA in the blood, and changes in the telomeres, caps on the end of chromosomes which are involved in the ageing process. First, there was a significant increase in average length while he was in space, and then there was a decrease in length within about 48 hours of his landing on Earth that stabilized to almost preflight levels. What's important is which changes space seems to have made on Scott Kelly's body. These epigenetic changes were likely the body's way of responding to the low gravity, oxygen deprivation, increased inflammation and diet challenges of space flight. The researchers discovered hyperactive immune activity as well, thought to be the result of his radically different environment: space. Kelly suffered from immune system hyperactivity, as well as bone and collagen formation abnormalities from his year in space. Kelly's one-year on the ISS is a good precursor for a three-year mission NASA hopes to soon launch to Mars. For almost a year, commander Scott Kelly living onboard the worldwide space station.

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