Scott and Mark Kelly are identical twins brothers. However, that notion was slightly changed after Scott Kelly came back to Earth after spending a year aboard the International Space Station. Upon his return, scientists quickly noticed that the astronaut’s genes were changed.
When Scott Kelly returned to Earth after a 340-day trek aboard the ISS two years ago, he was 2 inches taller than he’d been when he left. More so, his body mass had decreased, and his gut bacteria were entirely different. Now, a new NASA statement revealed that the astronaut experienced a seven percent change in his genes.
According to NASA, Scott Kelly’s year aboard the ISS may have activated hundreds of “space genes” that changed the astronaut’s immune system, eyesight, bone formation, and other bodily processed. The reason for this alteration, the agency believes, was due to the physical and mental stresses Scott Kelly was subjected to in space.
While most of the changes experienced in Earth’s orbit has since reverted upon his return, about seven percent of the astronaut’s genetic code remained altered.
Some changes returned to baseline within hours or days of landing, while a few persisted after six months,” NASA reports in its preliminary findings.
Scott Kelly’s year aboard the ISS was part of a project called the Twins Study. The goal of this project was to reveal the long-term effects of space travel on the human body and mind. Kelly is the first astronaut to have stayed aboard the ISS for 340 days. A typical stay aboard the ISS is for six months.
Meanwhile, Scott Kelly’s identical twin brother, Mark, who is a retired astronaut, remained on Earth as a control subject. According to NASA, the Kelly brothers are the only twin astronauts in history.
Scientists tested both Mark and Scott before, during and after Scott’s first year in space to map specific changes in his physical and mental health.
The genes that remained altered after returning to Earth dealt with bone formation, oxygen deprivation, immune system responses, and DNA repair.
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