NASA Twins Study: Space travel changes your DNA

Space travel is literally in an astronaut’s DNA, NASA’s Twins Study has revealed.

The study is investigating what space travel does to the human body by comparing astronaut Scott Kelly, who spent almost a year in space, to his identical twin brother Mark, a former astronaut who remained on Earth for the period of the study.

The Twins Study has put forward its first results, one of which showing space travel makes chromosomes larger.

twin study composite NASA space science

The scientists behind NASA’s Twin Study (Credit: NASA)

Telomeres on the ends of chromosomes in Kelly’s white blood cells became longer during his time in space, it was found. Reduced exercise and a lower calorie count while in space could explain this, according to researchers. His telomeres, which are known to decrease in length with age, shortened again once Kelly returned to Earth.

Kelly was found to be two inches taller when he came back to Earth in March 2016, but just as his height returned to normal once he came back, so did his DNA. Similarly, the astronaut’s level of chemical DNA modification slowed while in space before returning to normal after he came back to Earth.

Lower bone formation and higher stress

Bacteria in the gut was also something mentioned during NASA’s first release of information about the study. NASA’s website says that:

“One shift was a change in the ratio of two dominant bacterial groups (i.e., Firmicutes and Bacteroidetes) present in his GI tract. The ratio of one group to the other increased during flight and returned to pre-flight levels upon return to Earth.”

Other findings include the fact that bone formation slowed during the second half of the expedition, and the fact that a stress hormone increased as Kelly’s time in space went on.

The Twins Study encompasses ten investigations involving 12 universities, along with NASA biomedical laboratories and the National Space Biomedical Research Institute.


Image credit: NASA