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NASA study finds ‘space genes’ after astronaut’s year in orbit

Mark Kelly, left, and his twin brother, Scott Kelly, spoke to the media in 2015 before Scott Kelly’s mission.
Mark Kelly, left, and his twin brother, Scott Kelly, spoke to the media in 2015 before Scott Kelly’s mission. Robert Markowitz/NASA

An innovative study of an astronaut who went into space for a year and his twin brother who stayed on Earth has found that being in space affected that twin’s genes.

NASA’s Twins Study compared what happened, physiologically and psychologically, to Scott Kelly, who spent a year on the International Space Station, with what happened to his identical twin brother, Mark, who was earthbound.

One of the most intriguing findings from what NASA calls the “perfect nature versus nurture study” was that some of Scott Kelly’s genes had changed.

“Researchers now know that 93% of Scott’s genes returned to normal after landing,” NASA wrote in a statement.


However, “a subset of several hundred ‘space genes’ were still disrupted after return to Earth,” NASA said.

The changes were “thought to be from the stresses of space travel” and were “unexpected,” NASA wrote.

Christopher Mason, a professor at Weill Cornell Medicine who led the gene research on the Kellys, said the changes in gene expression, which were detected six months after Kelly landed, were believed to be a result of stresses such as the increased radiation in space and microgravity.

“This is the first study of its kind,” said Mason. “All of these measures are a first sketch of what is the molecular landscape inside a human that’s been in space this long.”

The changes might be specific to Scott Kelly, who returned to Earth two years ago, or they might be typical, said Mason, who says more research on future astronauts will shed more light.

Another interesting finding from the studies of the brothers: Kelly’s telomeres, which are the endcaps of chromosomes that shorten as a person ages, became significantly longer, NASA said. They also got shorter again within two days after he landed.

A total of 10 research teams worked on the Twins Study. The other teams’ focuses included the brothers’ cognitive performance, their immunological responses, and their gut bacteria.


Felicia Gans can be reached at felicia.gans@globe.com. Follow her on Twitter @FeliciaGans.