This sounds… odd.
A new study from NASA has found that astronaut Scott Kelly’s genes are no longer identical to those of his identical twin after spending a year in space.
Preliminary results from NASA’s Twins Study found that seven percent of Kelly’s genes no longer match those of his twin, Mark. Scott Kelly spent one year aboard the International Space Station during the study, while his brother remained on Earth.
More here. At first I assumed that it was just a radiation thing, but maybe it’s more of a freefall thing. I’m also slightly surprised about Mark Kelly’s telomeres lengthening while in orbit; if space tourism ever takes off, expect that to be a selling point for long-term habitation. Although, to be fair; free fall might not be a bad place to be old, on general principles. More bone and muscle development problems, but the strain on the heart is just going to be a lot less, too.
PS: Yes, the headline’s horrible. English major, remember?