UPDATED: How did astronaut Scott Kelly change in space?
Digital Reporter
Thursday, March 15, 2018, 3:18 PM - A year in space has left U.S. astronaut Scott Kelly a changed man, compared to his identical twin.
It's a headline that's been covered by several major news outlets, based on a tidbit from a NASA statement.
Here's the note-worthy quote:
"Although 93% of genes’ expression returned to normal postflight, a subset of several hundred “space genes” were still disrupted after return to Earth."
What does that mean?
What many outlets -- including The Weather Network -- initially reported was that Scott's DNA was altered upon returning to Earth, when compared to the DNA of his identical twin Mark. But, as science writer SciCurious points out in a recent Twitter thread, NASA is referring only to Scott's altered gene expression, and not the actual genes themselves. There's a difference.
"DNA gets transcribed to RNA, which is translated to protein .... What changed was the transcription and translation of some of S. Kelly's genes. NOT THE GENES," reads part of the Twitter thread.
"While in space, S. Kelly had changes to expression in the immune system, metabolism, reactions to low oxygen, stress responses, etc. When he got back? Most of that flipped right back too.
Some gene expression changes stayed around, like responses to low oxygen, and bone formation (we know astronauts lose bone density in space). Again, these are changes in how the DNA makes proteins. Not the DNA itself."
Why is this study important?
Identical twins Scott and Mark -- who is also an astronaut -- were subjects of a study aiming to determine what space travel does to the human body.
Scott resided on the International Space station between March 2015 and 2016, while Mark stayed on Earth, and NASA kept a close eye on both of them to monitor any differences.
Astronauts typically only spend six months aboard the ISS.
NASA says the study will help researchers plan for three-year manned missions to Mars.
Some of the changes in gene expression that NASA noted in Scott reverted to normal within hours of returning to Earth, while others remained changed six months later.
