NASA has confirmed the preliminary findings from its year-long Twins Study. The first-of-its-kind opportunity to study the genetic impact of space on the human body came about after astronaut Scott Kelly was chosen to serve aboard the International Space Station from March 2015 to March 2016. His identical twin, Mark Kelly, who is also a former NASA astronaut, remained on Earth.
During the course of NASA’s year-long mission aboard the International Space Station (ISS), researchers from 12 universities analyzed biological samples from both brothers to gauge the genetic shifts that might be taking place.
Scientists have found no long-lasting, major epigenetic differences in astronaut Scott Kelly, ), and his twin brother, Mark Kelly. Epigenetic changes involve chemical “tweaks” to DNA that can influence gene activity, but the changes don’t affect the underlying genetic code itself. The changes affect when and how a gene is read, or expressed, for its protein-encoding instructions.
There was a less than 5% difference in overall methylation between the twins during the mission. The scientists also observed cognitive changes and increased stress levels in Scott during the flight, which, again, may not be attributed to space flight alone.