 For the first time, scientists can now test the effects of microgravity and radiation on astronauts without having to account for the effects of genetics. This is your space pod for April 1st, 2015. On the 27th of March, astronaut Scott Kelly launched to the International Space Station for a one-year mission. His twin brother, Mark Kelly, remains on Earth. Identical twins share nearly 100% of their DNA. This is incredibly useful when you want to study the effects of environment on the human body. Let me explain. Usually, when we study the human body in space, we compare a group of people that have flown in space to a control group who have not. We have already made some cool discoveries using this technique, such as learning that bones weaken faster in space. However, what if, just by chance, all of the astronauts already had a genetic predisposition to weakening bones, while the Earthbound group did not. With our current genetic technology and the small sample size of astronauts that have flown in space, we cannot know for sure if it is the genes or the space environment itself that are causing these changes or even an interaction between the two. By using identical twins, we avoid this dilemma completely. So, what research will the twins be performing? There will be studies related to brain function, cell structure and metabolism, their circulatory and immune systems, and even the microbes that live inside their gut. My favorite research will be on changes to the DNA structure, in particular on a piece of their DNA called telomeres. Telomeres are the protective DNA sections that act like caps on the ends of our chromosomes. Every time our cells divide to form more cells, such as when we grow or repair our tissues, our telomeres shorten. After a certain amount of time, our telomeres can no longer shorten any more and these cells no longer divide to form new cells. This is an important part of the aging process. The cool thing, though, is that it is not just time that can make our telomeres shorten. Oxidative stress can cause extra shortening of our telomeres. Oxidative stress occurs when our cells are exposed to compounds called free radicals. Unfortunately, free radicals can be reduced in our body when we are exposed to cosmic radiation. This wouldn't be too much of a problem if the exposure was short, but long duration exposure, such as on space flight missions to Mars or on a moon colony, could allow a buildup of damage to levels that could affect our health. If telomeres are shortening faster in space, we could experience greater rates of aging and aging related diseases on long duration flights. This is a really important factor to consider for future missions. The good news is we may be able to prevent oxidative damage to our DNA. Antioxidants are particularly good at neutralizing free radicals. In spacefaring rats, it was shown that dietary supplements of antioxidants can prevent oxidative effects of space flight. Future astronauts could protect themselves through their diet or through taking antioxidant supplements. We could also research and design better radiation shielding on our next generation spacecraft, so we limit the amount of radiation our astronauts are exposed to. Actually, any improvements that we make to protecting and treating humans exposed to cosmic radiation could help people here on Earth, such as workers in the nuclear and medical radiation fields. Our research into telling me a shortening could also help improve lifespan and may slow the onset of aging related diseases. I can't wait to see the results of this study, although it will take a while. If you'd like to read more information about spaceflight and telomeres, check out the references below in the video description. Thank you for watching, and remember to subscribe to our YouTube channel at youtube.com to be notified when any new videos are released. We are a crowdfunded show, and if you would like to help contribute to the making of these videos, please head over to patreon.com. Stay tuned for next week, where I'll be discussing immune system research on the International Space Station.