Whoa! Scott Kelly Spent a Year in Space, and Now He Has Different DNA Than His Identical Twin Brother [livescience.com]
Yeah by 0.02 % . What got my attention was the fact that his telomeres lenghtened while up there. That is interesting, since our shorten as we age. it is the reason we age. so his lenghtening was interesting to say the least. BUT! after he returned they eventually shortened to the length of his brothers. but for a while he was younger!
That is bizarre.
I wonder how much of the changes are due to radiation. NASA's statement didn't mention it. I just happened to see a report on the show Seeker about growing plants on the ISS (which Scott Kelly worked on), which made me wonder if the plant DNA is also being effected.
[nasa.gov]
They have stated before that they knew that cosmic rays are a constant threat to the DNA so I'm sure it is partially responsible. But other changes like his telomeres lengthening would not be caused by radiation. So there has to be some other cause.