By Maddie Burakoff
...Researchers also studied Scott’s genome (click here) to see if gene expression changed during flight, as it tends to do in stressful situations. A team led by Chris Mason, a geneticist at Weill Cornell Medicine, studied DNA and RNA modifications that would signal epigenetic adaptation. They observed some changes in how genes were expressed, and these variations accelerated in the last six months of the mission. More than six times as many differences in gene expressions cropped up over the latter half compared to the beginning of the flight.
The findings were was somewhat surprising, Mason says, because he’d expected these differences to slow down or stop after an initial period of adaptation to the new environment. The sustained and increasing genetic transformations show that the body continues to change over long periods of time in space.
Andrew Feinberg, a professor and medical researcher at Johns Hopkins University, and his team focused on methyl groups—chemical markers that usually signal changes in gene expression—and found the amount of epigenetic change was similar for the two brothers. Despite some minor differences, Scott’s genome behaved in a way that was “not worrisome,” Feinberg says.
After the mission’s end, 90 percent of the modified gene expressions returned to their pre-flight baseline—a good sign that the body can bounce back after a long mission, Mason says. The other 10 percent, which comprised over 800 genes, including ones related to immune response and DNA repair, were still being expressed differently six months after Scott’s return. “It seems, to some degree, that enough cells in the body have a memory of what happened that there's still some ongoing adaptation and recalibration to being back on Earth,” Mason says....
