A Year in Space Changed an Astronaut’s DNA

Scott Kelly has found that his genetic code no longer matches that of his twin brother. (Photo courtesy of NASA)

When the United States space began its program in the 1950s, one of the things scientists studied the most was the effect of space travel on the human body and mind. What would exposure to cosmic rays do? Would leaving Earth’s atmosphere alter an astronaut psychologically? How would zero gravity affect the body?

As long term space travel – to places like Mars and even beyond – looms on the horizon, we’re looking at even more ways that the journey could enact change on the health of an astronaut, and NASA has just released one astonishing study. After a year at the International Space Station, the DNA of Astronaut Scott Kelly has changed.

NASA monitored the astronaut’s health and genetic makeup over his year orbiting the planet, and his genes underwent a change that differed from that of his twin brother Mark, also an astronaut.

Researchers now know that 93% of Scott’s genes returned to normal after landing. However, the remaining 7% point to possible longer term changes in genes related to his immune system, DNA repair, bone formation networks, hypoxia, and hypercapnia.

It’s worth noting that some of Kelly’s chromosomes that under normal circumstances would shorten with age actually lengthened in space. The agency studied his cognitive abilities as well.

Increasing mission duration from the typical six-month ISS mission to one year resulted in no significant decreases in Scott’s cognitive performance while inflight and relative to his twin brother Mark on the ground. 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.

NASA’s Twins Study was one of those landmark (and possibly once-in-a-lifetime…because, hey, how often do we have identical twin astronauts?) opportunities for the space program to discover what happens to someone over long periods of time outside the atmosphere. It will be fascinating to see how missions to Mars and wherever else our travels take us will alter the human body.

Wow. This is amazing. Just shows the glory of God Almighty that he could actually alter the genetic makeup of a person after they are born. Like the buried fossils of dinosaurs and the Big Bang - just another thing our Creator left for us to discover and learn about!