In article ,
says...

a study just complete prove long term stays in orbit cause dna changes

No cite? Of course not.


http://www.redorbit.com/news/space/1...s-study-space-
travel-changes-your-dna/

From above:

Telomeres on the ends of chromosomes in Kelly's white blood cells
became longer during his time in space, it was found. Reduced
exercise and a lower calorie count while in space could explain
this, according to researchers. His telomeres, which are known
to decrease in length with age, shortened again once Kelly
returned to Earth.

Kelly was found to be two inches taller when he came back to
Earth in March 2016, but just as his height returned to normal
once he came back, so did his DNA. Similarly, the astronaut's
level of chemical DNA modification slowed while in space
before returning to normal after he came back to Earth.

So, the changes were temporary and could be due to diet and (lack of)
exercise, not "long term stays in orbit".

Jeff
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