NASA is in the midst of a “Twins Study” that looks at the biological effects of long-term space habitation by comparing the physiology of one twin — who spent a year in space — with that of the other twin, who remained on Earth. Though the data is still rolling in, there are preliminary indicators that space does have a big impact on one’s biology, and the changes may range from things as ‘small’ as gut microbiomes to gene expression.
The study aims to help NASA and space researchers determine what kind of effects prolonged time in space has on the human body, and to then develop ways to mitigate any potential negative complications. Many researchers are involved in this study, including a dozen universities, 10 individual investigators, the National Space Biomedical Research Institute, and NASA’s biomedical laboratories.
The study involves astronaut Scott Kelly, who spent about a year in space, and his identical twin brother, Mark. Upon his return to Earth, researchers conducted extensive tests to determine what changes he experienced compared to his own before-space measurements and those in relation to his twin.
The preliminary results show that Scott experienced decreased DNA methylation during his flight while Mark experienced an increase. Upon Scott’s return, both their levels returned to normal. Scott is also said to have experienced larger than normal increases in gene expression signatures, which indicate his time in space had a direct impact, though the specific cause is unclear.
It seems the researchers have also noted a difference in lengths of the brothers’ chromosomes, and changes to Scott’s gut bacteria. We’ll no doubt hear more details about the changes as more data is collected and determinations about it can be made.