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article imageNASA study confirms initial findings — space can alter genes

By Karen Graham     Mar 13, 2018 in Science
Scott and Mark Kelly are identical twin brothers, and retired astronauts— the only identical twin astronauts in history. And the twin brothers presented NASA with a unique opportunity to study the effects of spaceflight on the human body.
Our nation's space program has grown increasingly sophisticated and ambitious. With future missions focusing on exploration at greater distances from our home planet, and extended stays in space being a requirement, mundane issues have grown in importance.
From the challenges of growing and providing nutritious foods to managing an environment fraught with risks from radiation, lunar dust, zero-gravity conditions, and more, the Human Research Program (HRP) was established as a result of NASA's refocus of the space program on exploration in early 2004.
The HRP is dedicated to discovering the best methods and technologies to support safe, productive human space travel, as well as educating the public about the challenges of human space travel. So when Scott Kelly was selected, along with Mikhail Korniyenko, for a special 340-day so-called year-long mission to the International Space Station, HRP was provided with the opportunity to study the medical, psychological and biomedical challenges faced by astronauts during long-duration spaceflight.
Scott Kelly (on the left)  and Mikhail Korniyenko (on the right)  were selected for the one-year mis...
Scott Kelly (on the left), and Mikhail Korniyenko (on the right), were selected for the one-year mission in 2012.
One-Year Mission & Twins Study
The two astronauts began their year in space on March 27, 2015, and returned to Earth on March 1, 2016. And while data from the 12-month expedition will help in formulating current assessments of crew performance and health, as well as validate countermeasures to reduce the risks associated with future exploration, the HRP also conducted a comparative study on the genetic effects of spaceflight with Scott’s twin brother Mark as the ground control subject.
As for the Twins Study, it encompassed 10 different investigators who coordinated and shared all data and analysis as one large, integrated research team. The study itself focused on four categories of research split into 10 investigations to evaluate the identical twin astronauts Scott and Mark Kelly.
As the saying goes, science takes time. Scott and Mark have identical DNA - the genetic code that tells cells when and how to work. So researchers tested both brothers before, during and after Scott's year in space to map specific changes in the astronauts' physical and mental health.
Identical twin astronauts  Scott and Mark Kelly  are subjects of NASA’s Twins Study. Scott (right)...
Identical twin astronauts, Scott and Mark Kelly, are subjects of NASA’s Twins Study. Scott (right) spent a year in space while Mark (left) stayed on Earth as a control subject.
And because different research laboratories were given different missions in the comparative study, it took about two years to come up with the preliminary results, and they’re quite interesting. Later in 2018, an integrated summary publication of the Twin Study is expected to be released.
Preliminary findings in the Twin Study
Measuring large numbers of metabolites, cytokines, and proteins, researchers learned that spaceflight is associated with oxygen deprivation stress, increased inflammation, and dramatic nutrient shifts that affect gene expression. After Scott returned to Earth from his year-long mission, it took his body time to re-adapt to Earth's gravity.
And most of Scott's physical changes, including his two inches in height gain, proved to be responses to the low gravity, low-oxygen environment of space, according to NASA. Some changes returned to baseline within hours or days of landing, while a few persisted after six months.
The Twins Study Investigators came from around the country to meet and share their final research re...
The Twins Study Investigators came from around the country to meet and share their final research results at the annual Human Research Program Investigators’ Workshop held in Galveston, Texas in January 2018.
Of particular interest were the changes to Scott's DNA. Scott’s telomeres (endcaps of chromosomes that shorten as one ages) actually became significantly longer in space. This unexplained anomaly was verified with multiple assays and genomics testing. However, most of the telomeres returned to normal lengths within two days of Scott's return to Earth.
Researchers now know that 93 percent of Scott’s genes returned to normal after landing. However, the remaining 7 percent point to possible longer-term changes in genes related to his immune system, DNA repair, bone formation networks, hypoxia, and hypercapnia. Hypercapnia refers to excessive carbon dioxide in the bloodstream, typically caused by inadequate respiration.
Increasing the mission from the typical six-month length to almost one year resulted in no significant decreases in Scott’s cognitive performance while in flight. But he did exhibit a pronounced decrease in speed and accuracy post-flight, which NASA attributed to Scott's re-exposure and adjustment to Earth’s gravity, along with his busy schedule.
The results of this study will be helpful in preparing for future space missions. There is no doubt that further research is still needed to understand what happened to Scott Kelly's DNA. This could be a significant issue in prolonged space travel.
More about NASA, twins study, Kelly twins, Telomeres, genetic profiling
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