Hi everyone,
Here is an article about DNA changes in space station astronaut, which no longer match his twin's.
https://edition.cnn.com/2018/03/14/health/scott-kelly-dna-nasa-twins-study/index.html***********
Spending a year in space not only changes your outlook, it transforms your genes.
Preliminary results from NASA's Twins Study reveal that 7% of astronaut Scott Kelly's genes did not return to normal after his return to Earth two years ago.
The study looks at what happened to Kelly before, during and after he spent one year aboard the International Space Station through an extensive comparison with his identical twin, Mark, who remained on Earth.
NASA has learned that the formerly identical twins are no longer genetically the same.
Although 93% of Scott's genetic expression returned to normal once he returned to Earth, a subset of several hundred "space genes" remained disrupted. Some of these mutations, found only after spaceflight, are thought to be caused by the stresses of space travel.
As genes turn on and off, change in the function of cells may occur.
Additionally, the team found changes in Scott's collagen, blood clotting and bone formation due, most likely, to fluid shifts and zero gravity. The researchers discovered hyperactive immune activity as well, thought to be the result of his radically different environment: space.
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Cheers.
Sriram