Space travel might be a touch stressful on the human body, Nature News says. Preliminary results from the NASA Twins Study have found differences in DNA methylation and gene expression in samples collected from astronaut Scott Kelly.
"[A]lmost everyone is reporting that we see differences," project researcher Christopher Mason from Weill Cornell Medical College tells Nature News.
All sorts of samples were collected from Scott Kelly and his twin brother Mark, a former astronaut, for analysis. While Scott orbited the Earth on the International Space Station for about a year, Mark remained on Earth. Since the brothers are identical twins with similar life experiences, researchers hope that by studying differences between the two, they'll be able to see how time in space affects the human body.
As Nature News reports, Johns Hopkins University's Andrew Feinberg's team has found that DNA methylation levels decreased in Scott while he was in space, though they increased in Mark during that same timeframe. For both, DNA methylation levels returned to pre-flight levels after Scott returned home. Meanwhile, Mason's team noted that there were gene expression changes between the brothers, and that the changes seen in Scott appeared to be greater than normal.
What these changes mean, isn't certain, but they could reflect, for instance, stress due to trying to sleep in little gravity or eating freeze-dried food, Nature News says.