Astronaut Scott Kelly spent a year in space, while his twin brother Mark Kelly — known to many around these parts as the husband of former Congresswoman Gabby Giffords — stayed on the ground. After a year, the elevated Kelly brother returned to Earth and spent a lot of time in enclosures even smaller than the International Space Station so he could be tested for the effects that long term exposure to free-fall and other aspects of space flight had on his body.
And, as you’ve likely heard if you watched the news at all this week, while in space, Scott Kelly’s genes changed. That phrase has been spoken with arched eyebrows and a big “ooooh” across the dial. The implication is that Kelly was exposed to something strange which did strange things to him up there in the void. Hosts from Fox to Today have made associations between this “gene change” and Kelly getting taller while in space. They’ve all but said the word mutant, as if they expected Scott Kelly to begin sprouting a third arm and maybe a pair of antenna.
But what happened to Kelly’s genes is not what all those TV folks have implied. It wasn’t that lack of gravity unraveled his DNA, or exposure to cosmic rays riddled his code with errors. What changed was his epigenetics. His genetic expression. The way his genes work within his cells.
Epigenetic change don’t represent an alteration in the DNA itself. All those little As, Cs, Ts, and Gs are still there, still in the same order. Scott Kelly likely suffered some damage to that code over the course of a year — all of us do — but that change was vanishingly small. Instead, some of the genes in his cells were … switched off. Or switched on. Or turned up or down. Everything you do has epigenetic effects. What you eat affects gene expression. Exercise, or lack of it, affects gene expression. Just getting older affects gene expression.
So it shouldn’t be surprising that Scott Kelly, after a year living in a unique environment, under very peculiar stresses, eating a very different diet, and not subject to the solid one-gee that tugs at all of us earthbound folk, should show some significant differences. What do those changes mean? Dammifino. And right now, neither do the scientists who are studying Scott Kelly.
But the most interesting thing that’s been discovered may be that about 7 percent of Kelly’s genes haven’t returned to baseline since he’s been back on Earth. These genes, which NASA researcher Chris Mason has labeled “space genes,” apparently had their activity modified over his year on the ISS in a way that seems to be persistent. From Mason’s study, there seems to be a decrease in the action of the mitochondria in Scott Kelly’s cells. This could have been triggered by above normal levels of CO2 in the ISS atmosphere. Maybe. Or maybe not. There were also changes in Kelly’s bones, something that NASA has seen in the past. Astronauts on long duration flights tend to shed a significant about of calcium from their bones. This probably come from the simple lack of stress applied to the long bones while in free-fall. With Kelly, they’ve probably pinned down the epigenetic response that goes along with this change.
In any case, Scott Kelly isn’t a mutant, and he’s not going to begin developing telekinesis — though that would be cool. Instead, the epigenetic changes in his cells are important to understand as we get ready to once again move beyond low Earth orbit and have more people in space for longer periods.
Okay, let’s go read some space news!
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