American astronaut Scott Kelly returned to earth in 2016 after spending a year in space, and he came back a changed man—at the DNA level.
Scott orbited our planet for 340 days, while his identical twin brother, Mark, stayed home.
Results from NASA’s Twins Study have confirmed that seven percent of Scott’s genes did not return to normal after he landed, NASA reported.
The aim of the study was to examine what happens to the human body after spending one year in space.
Researchers studied Scott in space both psychologically and physiologically and compared his results to those of his twin brother back home.
After Scott landed, 93 percent of his genes gradually turned back to normal, some within hours or days, others after six months, researchers found.
The altered 7 percent could be a sign of longer-term changes in genes related to his immune system, DNA repair, bone formation networks, hypoxia, and hypercapnia, according to NASA.