NASA Astronaut Scott Kelly's DNA Changed in Space

Wednesday, 14 Mar, 2018

The Twins Study is a collaboration between NASA and ten research teams from around the US, investigating how the human body is affected by spending a year in space.

Scott Kelly (on the left), and Mikhail Korniyenko (on the right), were selected for the one-year mission in 2012. A few, however, still affected Scott six months after his return. Scott and Mark have identical DNA - the genetic code that tells cells when and how to work.

A recent NASA statement suggests that the mental and the physical stresses of Scott's year in space might be responsible for activating numerous "space genes" that changed his immune system, eyesight, bone formation and various other bodily processes.

Scott's telomeres, the ends of chromosomes that shorten as you age, became significantly longer in space, but the majority of them shortened within two days of his return to Earth. A Mars mission would last as long as three years, which would obviously be the longest stretch that any human has been away from Earth.

The individual studies on the twins will be combined into a summary paper, as detailed in the graphic above. Ten research teams presented their preliminary findings previous year at NASA's Human Research Program 2017 Investigators' Workshop (IWS).

Of particular interest were the changes to Scott's DNA. "While this finding was presented in 2017, the team verified this unexpected change with multiple assays and genomics testing". However, most of the telomeres returned to normal lengths within two days of Scott's return to Earth. According to researchers, around 7% of Scott Kelly's genes have shown long-lasting changes when compared to his brother's. Researchers now know that 93 percent of Scott's genes returned to normal after landing.

However, seven per cent of the changes to Scott's genetic code remain, including some related to his immune system, DNA fix and bone formation networks that could potentially be permanent. Hypercapnia refers to excessive carbon dioxide in the bloodstream, typically caused by inadequate respiration. "However, a more pronounced decrease in speed and accuracy was reported postflight, possibly due to re-exposure and adjustment to Earth's gravity, and the busy schedule that enveloped Scott after his mission". The results of this study will be helpful in preparing for future space missions.

So far, only preliminary findings from the study have been released, as researches continue to analyze the changes within Scott's body. This could be a significant issue in prolonged space travel.