The most recent data from the twin study shows that 2 years after spending close to 1 year in space aboard the International Space Station, astronaut Scott Kelly’s DNA still has not returned to normal, it has been found that 7% of his genes have not returned to normal since returning to earth according to the 2018 NASA Human Research Program.
DNA was examined in this study of both of the identical twin brothers prior to the stay on board the International Space Station for 340 days and has continued to be checked for the genetic makeup of the pair over time to track changes, as a result of the changes to the astronaut’s genes the two brothers are no longer considered identical twins.
Much of the DNA changes in the astronaut have returned to normal, but 7% still remains altered, suggesting that those who spend extended periods of time in space travel will experience long term gene changes, these changes could have long term impacts on the immune system, bone formation networks, DNA repair, hypercapnia, and hypoxia.
NASA measured cytokines, metabolites, and proteins from the astronaut and found that spaceflight can cause changes with the body which can result in increased inflammation, dramatic nutrient shifts that affect gene expression, and oxygen deprivation stress. It was reported that telomeres, which are chromosome end caps that shorten with age, from the astronaut have become significantly longer while in space.
NASA will continue to monitor the twin brothers to determine if any other changes on the human body as a result of extended space time have/will occur. Bones and gut bacteria will be examined to try and determine how the immune system responds to life off of Earth for an extended period of time. Findings from this study may help NASA plan for other long term mission that require humans to live in space for extended periods of time, which includes the potential 3 year mission to Mars.
