[Edward64]

Beats me as to real implications but thought it was a neat story.

Scott Kelly: NASA Twins Study Confirms Astronaut's DNA Actually Changed in Space

Astronaut Scott Kelly’s DNA was altered by a year in space, results from NASA’s Twins Study have confirmed. Seven percent of his genes did not return to normal after he landed, researchers found.

Scott Kelly and his twin brother, Mark Kelly—also an astronaut—were the subjects of the study that sought to find out exactly what happens to the body after a year in space.
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In 2017, researchers discovered that the endcaps of Scott Kelly’s chromosomes—his telomeres—had become longer while he was in space. Further testing confirmed this change, and revealed that most of the telomeres had shortened again within just two days of his return.

After landing, 93 percent of Scott Kelly’s genes returned to normal, the researchers found. The altered 7 percent, however, could indicate long-term changes in genes connected to the immune system, DNA repair, bone formation networks, oxygen deprivation and elevated carbon dioxide levels.