@axolotl
A pretty cool, simple article looking at some of this. I also realized you werent talking about gene changes at the dna level looking back at your post. This could almost be tucked under your methylation thread.
Also notice bacterial changes outside of known specific changes to androgen expression.
No, space did not permanently alter 7 percent of Scott Kelly’s DNA
Some fascinating results have come out of the experiment. For one thing, Scott’s gut bacteria changed significantly while he was in space. And yes, he did experience genetic changes. The protective caps on the ends of his DNA strands — known as telomeres — increased while in space. But space didn’t permanently alter 7 percent of his DNA.
A person’s DNA is their body’s genetic code — the pattern and sequence of genes that make up the blueprint for the body. When a person’s DNA is altered, that means the pattern of genes in their body’s cells has been rearranged in some way. Perhaps some genes swap with one another, parts of the genetic code are removed, or new parts are added to a DNA sequence. External forces, like ultraviolet radiation from the Sun or smoke from cigarettes, can cause DNA mutations.
Now, the Twins Study did find that Scott and Mark had “hundreds of unique mutations in their genome,” and some of these changes were found after Scott got back to Earth, according to NASA. Bits of DNA were found circulating freely in his blood. The space agency thinks that this might have been caused by the stresses of space travel. Or it could have happened before he went to space — NASA just didn’t catch it until later. Even so, mutations in DNA aren’t that weird. “Mutation occurs all the time, as people get older,” Dan Arking, an associate professor of medicine at Johns Hopkins, who did not work on the study, tells The Verge .
What’s causing the ruckus, though, is that NASA found a shift in the way that Scott’s genes were expressed . That’s an entirely different thing than seeing a change in a person’s DNA. Gene expression refers to how active a particular piece of DNA is. DNA produces little tiny messengers of information known as mRNA, which cells use to make proteins that carry out all of your body’s basic functions. Gene expression refers to how much mRNA a gene produces. So the DNA stays the same; it’s just behaving differently.
“TO HAVE 7 PERCENT OF HIS GENE EXPRESSION CHANGED AFTER THE SPACEFLIGHT DOES NOT MEAN THAT 7 PERCENT OF THE DNA CHANGED.”
Scientists studying Scott found that much of his gene expression changed while in space, and about 93 percent of his expression levels went back to normal when he got home. However, 7 percent of his genes related to the immune system, DNA repair, bone formation, and more were still a little out of whack when he returned. These genes are referred to as the “space genes,” according to NASA.