Scott Kelly made news when it was revealed that the astronaut's time in space had altered his gene so much that they were now different from that of his twin brother Mark Kelly. NASA has now confirmed that space travel can alter a person's genetic makeup.
Scott Kelly spent almost a year in space.
Scott Kelly's genes were altered due to the stresses of space travel. This change can stick around with a person even after they return to Earth. Scientists found that after spending a year in space, Scott Kelly's genes were no longer an exact match to his brother Mark. Scott and Mark Kelly were part of the Twin Study by NASA to determine the effects of space travel on humans.
Scientists were not expecting this change in his genetics. NASA also found hundreds of unique mutations. Scott developed significantly longer telomeres in space. Telomeres cap off chromosomes and regulate the aging process.
Findings show that about 93 percent of the changes in his genes were temporary and Kelly's genetic profile returned to normal after he came back to Earth. About 7 percent of the changes have not reverted to the way he was before he spent the year in space. This includes changes in his immune system, DNA repair process, bone formation networks, oxygen deficiency in the bloodstream, and an excess of carbon dioxide in the bloodstream.
Changes like the longer telomeres disappeared after 48 hours of being back on Earth. Most of the changes that Scott Kelly went through disappeared after hours or days of his return to Earth, but some changes stayed with him after six months.
NASA concludes that this may point to longer-term changes in DNA. Kelly joked about the changes in his DNA by stating that he would no longer have to call Mark Kelly his identical twin.
Long-Term Space Travel
NASA's study into the changes may shine a light on the possibility of people traveling to other planets. Humans bodies are resilient, but they're protected from the amount of radiation found in space due to the magnetic field that surrounds the planet. Once astronauts are in space, radiation can be harmful. In the case of Scott Kelly, his DNA has been altered for good.