字幕表 動画を再生する 英語字幕をプリント Getting more sleep doesn’t just help you wake up refreshed in the morning. It can also literally keep you young. New studies show that those who are under stress and don’t get enough shuteye could age up to six times faster than they would otherwise, giving a whole new meaning to the term beauty rest. It all comes down to a part of our genetic toolkit called our telomeres. See, we’re made up of approximately 30-40 trillion cells of human tissue, and the DNA for each of those cells is tightly coiled up into chromosomes, which are housed in the nucleus of each cell. While we’re just living our lives, going about our business, our cells are replicating all the time. Every time a cell divides, the chromosomes have to be copied as one cell splits into two during mitosis. And during that cell replication process, telomeres act as protective caps on the ends of our chromosomes. Like, if our chromosomes are shoelaces, then telomeres are the little plastic tips on the ends of those shoelaces that keep them from fraying away. In most living things, including us, telomeres are made of hundreds to thousands of repetitions of the simple nucleic acid sequence TTAGGG. This cap does a lot of things, including telling our cellular machinery where one chromosome ends and another begins. They also serve as a buffer during the copying process, because cell replication isn’t perfect. The little tool that does the DNA copying isn’t as precise as you might hope, and can’t properly replicate the very ends of the chromosomes—this can cause a lot of issues, and is called the end replication problem. To avoid that chop-chop happening to your actual DNA—y’know the important stuff that tells your cells what to do—your telomeres take the hit instead and every time a cell divides, a little chunk of the telomere is lost in the process. So telomeres shorten with each cell division, but they also get shorter as you age. Like, even when you’re producing new cells, your telomeres are now shorter than they once were when you were younger, a trend called ‘telomere attrition’. This means that your chromosomes are less protected from damage during cell replication. Which is what scientists believe could be behind the decreased function and wellness of our bodies as we age, and could lead to degenerative diseases like Alzheimer’s. This info may now have you wondering, ‘well jeez, Louise, what do I have to do to keep my telomeres from shortening as I age?' On a certain level, there may not be much you can do about it. Your telomeres’ length and how fast they shorten throughout your lifetime is highly variable. Estimates say anywhere from 30-80% of your telomere’s characteristics could be due to genetic factors and other things out of your control like your father’s age at the time you were conceived. But, there’s good news: there are some things under our control. While telomeres are the protectors of our DNA, they are also very susceptible to damage themselves by—most notably—stress. Stress is an ambiguous word, but can come in a multitude of forms: smoking, obesity, exposure to trauma, a psychological disorder like major depression, and so much more, all of which can lead to physical effects like higher levels of stress hormones and the presence of inflammation. Which are associated with acceleration of telomere shortening. And as we’ve already established, telomere shortening is not good for your health. Just thinking about telomere shortening is stressing me out and probably shortening my telomeres! Man, I really need to get more sleep. Exercising, staying away from cigarettes, doing what you can to destress might actually add years to your life in the form of telomere length preservation. But saving your telomeres from excess shortening won’t necessarily save you from the things you’re genetically predisposed for. It just means they may happen to you later, rather than sooner. And aside from making good lifestyle choices, there may be something we can take advantage of to lengthen our telomeres built right into our cellular machinery. Telomerase is an enzyme that lengthens telomeres. In our adult stem cells, which is where new cells in our body come from, and our germ cells, which make sperm and eggs, telomerase is busy building those telomeres back up. If we could somehow get telomerase to build back the telomeres in our somatic cells, our regular body cells, that would be great! But the problem is that turning telomerase on is actually associated with cancer because, again, cells aren’t meant to just replicate forever and if they do, it can be a problem. These complex questions about telomere length and what we can do about it is a huge research field and we are just skimming the surface here, so let us know if there’s something in particular you’d like us to cover. All this telomere business has really important implications for our future in medicine and other kinds of innovation. Dolly the cloned sheep, for example, was born with shortened telomeres and actually died prematurely, telling us we’ll need to take telomere science into consideration when working on extremely ambitious synthetic organisms. Scott Kelly, the astronaut who spent a year aboard the International Space Station, experienced significant telomere shortening due to the stress his body was exposed to in space. And now you have some serious scientific backing when saying that taking some chill time is good for your health. Fun Fact: Telomeres are made of the same amino acid sequence in almost every prokaryote, meaning they are HIGHLY conserved. Your telomeres are the same as a protists, as a sloths, as a ladybugs. That’s pretty cool. Wanna know more about what happened to Scott Kelly’s DNA during his year in space? Check out this video here and make sure to subscribe for more genetic deep-dives. Thanks for watching.