Space travel caused lasting changes to seven per cent genes of astronaut Scott Kelly, according to a NASA study which compared his DNA to that of his identical twin brother, who remained on Earth.
NASA’s Twins Study brought ten research teams from around the country together to accomplish one goal – discover what happens to the human body after spending one year in space.
NASA has a grasp on what happens to the body after the standard-duration six-month missions aboard the International Space Station (ISS), but Scott Kelly’s one-year mission is a stepping stone to a three-year mission to Mars.
In 2017, ten teams had presented their preliminary findings at NASA’s Human Research Programme (HRP) Investigators’ Workshop (IWS).
Reports included data on what happened to Scott Kelly, physiologically and psychologically, while he was in space, and compared the data to Mark Kelly, as a control subject on Earth.
This year’s IWS findings from 2017 were corroborated, with some additions.
Researchers also presented what happened to Scott after he returned to Earth, again while making comparisons to Mark.
Later this year, an integrated summary publication is expected to be released.
By measuring large numbers of metabolites, cytokines, and proteins, researchers learned that spaceflight is associated with oxygen deprivation stress, increased inflammation, and dramatic nutrient shifts that affect gene expression.
After returning to Earth, Scott started the process of re-adapting to Earth’s gravity.
Most of the biological changes he experienced in space quickly returned to nearly his pre-flight status.
Some changes returned to baseline within hours or days of landing, while a few persisted after six months.
Scott’s telomeres – end caps of chromosomes that shorten as one ages – actually became significantly longer in space.
While this finding was presented in 2017, the team verified this unexpected change with multiple assays and genomics testing.
A new finding is that the majority of those telomeres shortened within two days of Scott’s return to Earth.
Researchers now know that 93 per cent of Scott’s genes returned to normal after landing.
However, the remaining seven per cent point to possible longer term changes in genes related to his immune system, DNA repair, bone formation networks, hypoxia and hypercapnia.
Increasing mission duration from the typical six-month ISS mission to one year resulted in no significant decreases in Scott’s cognitive performance while in-flight and relative to his twin brother Mark on the ground.
However, a more pronounced decrease in speed and accuracy was reported post flight, possibly due to re-exposure and adjustment to Earth’s gravity, and the busy schedule that enveloped Scott after his mission.