There are those who believe that we are masters of the environment. However, this idea is just as true as the belief that identical twins are identical. Far from masters, we are the products of our environment. This becomes more evident in a recent study involving identical twins and space.
A large consortium of researchers (including ones from NASA) conducted a study in which identical twin astronauts, Scott and Mark Kelly, were separated for about a year (Garrett-Bakelman et al., 2019)—one kept on Earth, the other launched into space. The researchers collected nearly every single type of data imaginable to determine how the environment of space (i.e., weightlessness, radiation, isolation, artificial settings, etc.) affects the human body compared to the environment of Earth.
Unsurprisingly, they saw that the space twin’s DNA took on some damage from radiation, such as an increase in the “translocation” of some DNA segments from one chromosome to another. There was also a type of DNA change that occurred frequently: The “flip” of a section of DNA within a chromosome, or an “inversion,” which happened during the cells’ efforts to repair radiation damage.
The researchers also noted a peculiar event happening to the twin while he was in space. He got “younger.” No, he did not return to Earth appearing twenty years younger. The space twin’s telomeres (ends of the chromosomes that shorten over time and used as markers for aging) got longer. The newfound youth, however, soon faded away upon the twin’s return to terra firma. This begs the question of just how reliable is telomere length when assessing age?
In addition to the increased DNA damage and yo-yo behavior from “age markers,” the signals used to communicate between cells reacted to the body being shifted between Earth’s gravity and the weightless space environment (and vice versa). With limited proteomic capabilities and genomic information, the team noted changes in risk of cardiovascular disease, inflammation pathways and dimensions of the heart. One wonders if any of these signals could be a better indication of – want to say something about proteins being great for looking at real-time health status.
The information collected on the astronaut twins was extensive, but not complete. One can only imagine what the researchers may have learned if they had been able to use SomaLogic’s insightful proteomic capabilities to monitor the real-time changes occurring within the space twin’s body and what elevated risks space travel pose for humans. Nevertheless, the information collected is a good start, and the physiological differences they observed after a year in space is a stern reminder that we are the products of our environment and not its master.
Garrett-Bakelman, F. E., Darshi, M., Green, S. J., Gur, R. C., Lin, L., Macias, B. R., . . . Turek, F. W. (2019). The NASA Twins Study: A multidimensional analysis of a year-long human spaceflight. Science, 364(6436). doi:10.1126/science.aau8650