Astronaut's DNA No Longer Matches Identical Twin After Year in Space

NASA has published preliminary findings from its Twin Study, revealing that the DNA of astronaut Scott Kelly was altered by his trip to space, and no longer matches that of his twin brother, Mark.

The Kelly brothers are identical twins, which should mean that their DNA is exactly the same. The National Aeronautics and Space Administration used this knowledge to conduct an experiment, hoping to learn if space travel effected human DNA on a fundamental level. The early results show that 7% of Scott Kelly's genes are different now than they were when he went up into space.

Scott Kelly spent a full year on the International Space Station, returning about two years ago. Since then the agency has extensively tested the effects on his body, and compared him to his (formerly) identical twin to assess the changes.

According to the study, scientists measured the Kelly brothers' metabolites, which are necessary for maintaining life, cytokines that are normally secreted by cells in the immune system, and proteins -- the powerhouses within each cell. They took these measurements before, during, and after the mission, and their results so far show that the stresses of spaceflight can fundamentally affect gene expression.

Scientists link the changes specifically to oxygen-deprivation stress, an increase in inflammation and a dramatic shift in nutrients. Chris Mason, of Weill Cornell Medicine called this process the activation of Scott Kelly's "space genes."

The changes in Kelly's physiology have persisted even after his return to earth. Many of the new mutations have only been found in the genes of those who have travelled in space.

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The report on these findings was written by Monica Edwards and Laurie Abadie of NASA Human Research Strategic Communications, and edited by Timothy Gushanas. It posits that the findings from Kelly's extended stay in space will help prepare researchers for planning a three-year-long manned mission to Mars at some point in the future.

"Research from the landmark Twins Study will inform NASA’s Human Research Program studies for years to come, as NASA continues to prioritize the health and safety of astronauts on spaceflight missions," they wrote.