After spending a year in space, NASA astronaut Scott Kelly’s DNA had slightly changed.
According to a preliminary report from NASA released in January, Kelly’s DNA had altered by seven per cent — no longer matching his identical astronaut twin brother Mark. The results were part of NASA’s year-long Twin Study, focusing on how space travel can affect the human body.
Kelly, who has been back on Earth for two years now, still has a small amount of genetic makeup that was similar to when he was in space.
Dr. Richard Wintle, assistant director of the Centre for Applied Genomics at SickKids hospital in Toronto, says it’s not so much Kelly’s DNA has changed, but rather how a person’s genetics are switched on and off during a period of time.
“Your genome is a complicated place and it’s made up of genes that do all kinds of things in your body… from development to creating tissue.”
After finding out seven per cent of his DNA had changed, Kelly joked about no longer being Mark’s identical twin.
“What? My DNA changed by 7%! Who knew? I just learned about it in this article. This could be good news! I no longer have to call @ShuttleCDRKelly my identical twin brother anymore,” he wrote on the social media site over the weekend.
The 54-year-old now retired astronaut went to the International Space Station in March 2015.
Being the first of its kind, the study followed Kelly during his year in space, as well as Mark’s year on Earth as a control subject. The study brought 10 different research teams together in the U.S., to figure out what could happen to the human body when it enters space. The study, NASA notes, is a “stepping stone to a three-year mission to Mars.”
NASA’s full findings should be released sometime this year.
According to researchers, 93 per cent of Kelly’s genes returned to “normal” after he landed, and the other seven per cent could be related to changes in his immune system, DNA repair, bone formation networks, hypoxia (the oxygen reaching his tissues), and hypercapnia (a condition when there is too much carbon dioxide).
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Last fall, Chris Mason, associate professor of the Department of Physiology and Biophysics at Weill Cornell Medicine in New York City, said this seven per cent refers to Kelly’s “space genes.”
Mason and his team looked at the twins’ chemical changes in RNA and DNA, CNN reports, and found that each astronaut had “more than expected unique mutations in his genome.”
“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,” researchers note.
They also add when Kelly came back to Earth, most of his body’s biological changes quickly returned to his pre-flight status. Other changes took hours or days to appear, while some changes happened after six months, the report continues.
Wintle says it’s no surprise some of Kelly’s genetic makeup changed in space and it’s also not so surprising some of it continued to stay the same.
“He’s done something extreme and unusual… it’s not so surprising that different genes are active in space.”
He explains one possible reason of why his genes remain unchanged (for now) is that whatever genes were turned on in space, may still be working to repair itself on Earth. Exposing your body in space, he adds, also means exposure to cosmic radiation, which could explain changes in Kelly’s bones, for example.
He adds there is also evidence that space travel can also affect bone density and muscle loss.
More research to come
Wintle adds because the sample size of this report is small — it is only comparing Kelly to his identical twin — it would be interesting to see this done on a larger scale with another set of twins.
NASA plans on releasing the full report in the spring of this year, and will also focus on the health and safety of astronauts during missions, Newsweek reports.