Famous for teasing out the effects of nature and nurture, studies comparing twins are a hallmark of research in many fields, including psychology, biology and medicine. Now NASA is preparing to run the first twin study in space, comparing how identical twin astronauts fare while one spends a year in orbit and the other remains on the ground.
Scott Kelly, along with Russian cosmonaut Mikhail Kornienko, is due to spend a full year living on the International Space Station from spring 2015 to spring 2016. Meanwhile Mark Kelly, Scott’s six-minutes-older brother and a retired astronaut, will live his normal life on the ground, undergoing periodic medical tests that will match those being performed on Scott in space.
Identical twins share essentially all their DNA, so any differences between them, the thinking goes, must be attributable to environmental disparities (that is, nurture, not nature). Spaceflight is known to cause bone-density loss, muscle atrophy, eyesight damage, a weakened immune system, sleep disturbance and a host of other problems. But why these symptoms differ among individuals is less well understood and may be partly attributable to genetics. By comparing Scott with Mark, as well as with Kornienko, NASA scientists hope to explore how DNA affects these changes. “It offers an opportunity for an extra control to see if that can help us better understand this long-duration spaceflight process,” says International Space Station program scientist Julie Robinson. Via Scientific American.