Nowadays the term “fake news” is usually associated with politics, but it’s worth remembering that no field is immune to the spread of misinformation. And pop-science journalism is at least as prone to distortion as political coverage, especially when simplistic headlines are exaggerated on social media.
This week saw a prime example of this problem. From its earliest days, NASA has studied the physiology of the men and women it sends up into space. Some readers may remember the scenes in The Right Stuff (both the book and the movie) in which John Glenn and the other original Mercury 7 astronauts had to pass a battery of physical examinations; decades later, when then-senator Glenn went back into space aboard the space shuttle, that return trip was supposedly for the purpose of gerontological research. By now we know a great deal about how time spent in space—with reduced gravity and increased radiation—affects bones, muscle mass, blood vessels, digestion, mucous membranes, and other aspects of physiology and bodily function.
The news that went viral this week relates to Scott and Mark Kelly—brothers, retired Navy officers, and experienced astronauts. Mark Kelly went on four shuttle missions between 2001 and 2011, each of which had a duration of about two weeks. Scott Kelly went into space on two shuttle missions in 1999 and 2007, then in 2010-2011 spent five months aboard the International Space Station, and another eleven months aboard the station in 2015-2016.
Because the Kellys are the only known siblings to have gone into space—and more importantly, because they are identical twins and so have almost exactly identical genes—their experience offered an interesting opportunity to study how time spent in space can affect genetics. Researchers could examine both Kellys before Scott’s long space stint—studying their bodies, testing their cognitive performance, analyzing their DNA—and then again after Scott’s return. It’s an exaggeration to call it, as NASA did in a January press release, “the perfect nature versus nurture study”—because no study with a sample size of one should be called “perfect,” and no study of two men in their 50s can really say much about “nature versus nurture”—but it was a fine opportunity to add incrementally to our knowledge about the effects of low gravity, increased radiation, and other aspects of space.
It is unclear why the news about the study went viral this week, since no paper describing the results in detail has been published yet and the “preliminary findings” that have been getting the headlines this week were actually announced several weeks ago. But viral it went. Here’s how some news outlets described it:
- Newsweek: “NASA Twins Study Confirms Astronaut’s DNA Actually Changed in Space”
- CNN: “Astronaut’s DNA no longer matches that of his identical twin, NASA finds”
- Live Science (via Twitter): “Scott Kelly Spent a Year in Space, and Now He’s No Longer His Brother’s Identical Twin”
- A reporter on NBC stated that “7 percent of Scott Kelly’s genes did not return to normal following his return to earth” and said that Kelly’s time in orbit “may have activated what scientists are now calling ‘space genes’”
There are many, many more examples of news outlets reporting the story in this way and of social-media users breathlessly circulating it.
The problem: These stories grossly distort the facts. The real record, based on what NASA has released so far, does not support the ideas that (1) Scott Kelly’s DNA changed; (2) that the Kellys are no longer twins; or (3) that some strange “space genes” have been activated. It’s worth looking at each of the three relevant findings (again, based on just what has preliminarily been released).
First, a team led by researcher Chris Mason of Weill Cornell Medicine studied changes in “DNA and RNA methylation.” Without getting too technical, methylation is a constant, ongoing process associated with “gene expression”—sometimes described as “activating” or “deactivating” genes. At least based on the preliminary summary from NASA, Professor Mason’s key finding relates not to changes in the makeup of Scott Kelly’s genes during his time in space but to changes in his gene expression.
This is where the 7 percent figure comes in: Apparently, 93 percent of Kelly’s genes returned to normal expression after his return to earth, while at least 7 percent continued to show abnormal patterns of expression for a time after his return to earth. Mason apparently coined the term “space genes” to refer to genes already present that in some way were found to show different patterns of expression in Scott Kelly. But we know that changes in methylation can be associated with exercise, obesity, smoking, and perhaps trauma—so it would make as much sense to say there are “obesity genes,” “exercise genes,” “smoking genes,” and so on.
Second, a team led by researcher Susan Bailey of Colorado State University studied the Kellys’ telomeres. Telomeres, sometimes called the “endcaps” of the chromosomes, are made up of the same nucleotides as the DNA in your genome—the A, C, G, and T nucleotides you may remember from high school biology. But they do not contribute to your genetic makeup.
Generally speaking, a decline in telomere length is associated with aging: older people tend to have shorter telomeres, which may be associated with various aging processes. There have also been studies suggesting that alterations in telomere length are somewhat associated with (again) exercise, smoking, and obesity. In the case of Scott Kelly, NASA reports that his telomeres “significantly increased in average length while he was in space” while his earthbound brother’s telomere length stayed “relatively stable.” But does that finding mean we have learned anything significant about telomeres or aging or spaceflight? Not really. The sample size (just one astronaut in space) is so small that it tells us very little. Scott Kelly’s telomere length may simply have been affected, the NASA press release explains, by “his rigorous exercise regime and restricted caloric intake.”
Finally, a team led by researcher Andy Feinberg of Johns Hopkins investigated the effects of Scott Kelly’s trip on not specific genes but his genome as a whole. Most of the effects they found “were well within the range of variability of his twin on Earth,” and the instances of changes in gene expression that the researchers found “returned to baseline” after Kelly landed.
In summary: The researchers found some small changes related not to Scott Kelly’s gene sequence but to gene expression and telomere length; most of those changes were small, and were likely just the epigenetic side of the physiological changes we already know are associated with space travel; many of those changes could have resulted from environmental differences not unique to space travel, such as variations in diet and exercise; and most of those changes disappeared soon after his return from the space station.
If you have questions about this fact check, or would like to submit a request for another fact check, email Holmes Lybrand at [email protected] or the Weekly Standard at [email protected]. For details on TWS Fact Check, see our explainer here.
