NASA Twins Study reveal changes in DNA after a year in space

Scott and Mark Kelly were subjects of NASA's Twins Study. (NASA)

The National Aeronautics and Space Administration (NASA) has released its preliminary findings from its Twins Study, confirming that after spending time in space, the genetic expression of an astronaut no longer matches his twin’s.

The study featured astronaut Scott Kelly, who spent one year aboard the International Space Station, and his identical twin Mark. It revealed that seven percent of Scott’s genetic expression changed compared to Mark’s after his stint in space.

A percentage of Scott’s genetic expression that underwent change did not revert back to baseline after his return to the Earth’s surface more than two years ago.

NASA explained that after readapting to Earth’s gravity, most of the biological changes that Scott’s body experienced in space reverted back to their pre-flight status. However, there are few changes that persisted six months after his return to Earth in March 2016.

Scott expressed surprise as he shared NASA’s findings in a tweet. “What? My DNA changed by 7%! Who knew? I just learned about it in this article,” wrote Scott, who became the first American astronaut to spend almost a year in space after spending 340 days in space..

“This could be good news! I no longer have to call @ShuttleCDRKelly my identical twin brother anymore,” he said of his brother in jest.

Despite the changes, Scott and Mart are still identical twins, as changes in gene expression are the result of the human body’s reaction to its environment.

The study allows NASA to gain much-needed insight into the changes that happen to the human body as a result of spending time in space beyond the usual six-month ISS missions. The study continues to look at the data from the Kelly twins, with 10 groups of researchers assessing information about bacteria, bones and the immune system. The findings will help future endeavors that seek to put humans on the nearby planet Mars.