A NASA ‘twins study‘ examined the effects of being in space on the human body by comparing data from astronaut Scott Kelly, who spent 340 days aboard the International Space Station, with that obtained from his twin brother, Mark Kelly, who stayed on Earth. Researchers involved in the study discovered that being in space was similar to being in a stressful environment: the body reacts to space like it would to stress.
While the actual statement about the results of this study was released more than a month ago, it created a lot of excitement in the media last week, almost all for the wrong reasons.
The twins study aimed to identify which genes and gene expression levels were influenced by spending long periods of time in space. For this, researchers sequenced Scott’s genome, recorded the expression profiles of his genes, and studied his immune system, metabolites and proteins following a six-month rest after a year in space. They had logged the same data before he left as well, and so had ‘before’ and ‘after’ datasets.
Similar measurements were performed on Mark, both before and after Scott’s space journey. Scott and Mark have almost the same genome, so comparing Mark’s ‘before’ and ‘after’ sets would indicate the basal level of changes expected in Scott’s genome and gene expression if he had stayed on Earth.
The study found that while 93% of Scott’s gene expression had returned to preflight status, 7% had not. The latter was mainly in genes activated during oxygen deprivation, inflammatory immune responses and when nutrient intake shifts drastically.
The first step to Mars
The study showed that hypoxia, triggered by a lack of oxygen and an excess of carbon dioxide, is one of the major risks associated with spaceflight. According to CNN, this could also have been responsible for damage to the mitochondria – little organelles that power each cell – in Scott’s body.
Researchers also found that the telomeres, parts of the chromosome that prevent loss of important genes, in Scott’s cells increased in length during spaceflight but shortened to normal just two days after he returned.
Usually, telomeres get shorter with age. Susan Bailey, a professor of radiation cancer biology at Colorado State University, Fort Collins, who conducted this part of the study, said this was probably due to reduced caloric intake and increased exercise when Scott was space.
The researchers also reported no changes in Scott’s cognitive ability during spaceflight. They reasoned that a decrease in speed and accuracy, observed after the trip, was possibly because the astronaut had been re-exposed to Earth’s gravity and his busy schedule immediately after landing.
They also observed a decline in bone formation during the second half of his space mission. According to CNN, this was probably due to a lack of gravity. Other changes included composition of bacteria in the gastrointestinal tract and small chemical modifications on the DNA called methylation, both of which returned to normal after two days on Earth.
The objective of the study was to determine the physiological and psychological effects of spending long periods – in this case one year – in space. Its findings will help guide a manned mission to Mars, according to NASA.
Woeful media coverage
However, what became the news was not the study’s conclusions but how they were widely misreported. Some even claimed that Scott and Mark Kelly were no longer alike thanks to the former’s sojourn in space.
Reporters from outlets like CNN and Business Insider got the story completely wrong, often confusing gene expression with the genes themselves. Genes are the physical DNA strands in cells. Gene expression is how much of an effect these genes have on cells. Altering one’s genes is far more difficult than altering one’s gene expression; in fact, the latter happens in our bodies almost every day. Both publications corrected their stories later.
CBS Denver claimed that Scott had “different DNA from his identical twin Mark Kelly”.
In reality, it was only the levels to which different genes get activated that had changed, not the genes themselves. The Telegraph claimed that “NASA astronaut twins Scott and Mark Kelly” were “no longer genetically identical after space trip”. Scott was amused.
What? My DNA changed by 7%! Who knew? I just learned about it in this article. This could be good news! I no longer have to call @ShuttleCDRKelly my identical twin brother anymore. https://t.co/6idMFtu7l5
— Scott Kelly (@StationCDRKelly) March 10, 2018
The ruckus forced NASA to issue an update to their statement on March 15, which said, “Mark and Scott Kelly are still identical twins; Scott’s DNA did not fundamentally change.” The agency added that the change in gene expression levels is “likely within the range for humans under stress, such as mountain climbing or scuba diving.”
Ars Technica urged journalists to not rush to cover a story just because others were doing it, and to verify facts before publishing.