WEBVTT - What Did NASA's Twin Study Find?

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<v Speaker 1>Welcome to brain Stuff, a production of I Heart Radio. Hey,

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<v Speaker 1>brain Stuff, Lauren Boglebam here. Have you ever wondered exactly

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<v Speaker 1>what happens to the human body when it's suspended in

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<v Speaker 1>space for an extended period of time? Based on Hollywood

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<v Speaker 1>productions alone, men and women who navigate the galaxy always

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<v Speaker 1>seemed to be just fine when they land back on Earth.

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<v Speaker 1>But are astronauts so lucky in reality? NASA has made

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<v Speaker 1>it its mission to find out. In a landmark DNA

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<v Speaker 1>study published in April nineteen issue of the journal Science,

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<v Speaker 1>researchers from John Hopkins, Stanford and other institutions revealed after

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<v Speaker 1>a year in space, astronauts Scott Kelly experienced no major

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<v Speaker 1>long term differences to his epigenome compared with that of

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<v Speaker 1>his twin brother, current Arizona Senate candidate Mark Kelly, who

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<v Speaker 1>stayed firmly planted here on Earth. Your epigenome is all

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<v Speaker 1>of the chemical compounds that have attached to your DNA

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<v Speaker 1>and changed the way it functions, so no major differences

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<v Speaker 1>is hypothetically a good thing. Here's the deal with putting

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<v Speaker 1>your body in space. It exposes you to harmful ultra

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<v Speaker 1>violet rays radiation, limited food and exercise, lower gravity, disrupted

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<v Speaker 1>sleep cycles, and an unknown number of other potential hazards.

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<v Speaker 1>And while scientists have spent decades studying the effects of

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<v Speaker 1>space travel on astronauts, most of these men and women

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<v Speaker 1>have traveled on missions that macks out at six months.

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<v Speaker 1>In order to travel somewhere like say Mars, missions need

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<v Speaker 1>to be much longer, and scientists say it's critical to

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<v Speaker 1>understand the effects that these super extended missions could have

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<v Speaker 1>on the human body. Let's talk more about how your

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<v Speaker 1>epigenome works. Your DNA is your genome. It's the genetic

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<v Speaker 1>code that tells every cell in your body how to

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<v Speaker 1>build different proteins, which determines how those cells function. Your

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<v Speaker 1>epi genome is any chemical modifications to your d NA.

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<v Speaker 1>These modifications don't change your actual DNA sequence, but they

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<v Speaker 1>can change how your cells use the instructions that your

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<v Speaker 1>DNA gives them. So these tiny chemical alterations can have

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<v Speaker 1>a major impact on a person's health by influencing the

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<v Speaker 1>way their genes are expressed. They can switch genes from

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<v Speaker 1>on to off, and vice versa. A major advantage of

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<v Speaker 1>this new research is the fact that it studies identical

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<v Speaker 1>twins who naturally have identical genetic material. But while the

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<v Speaker 1>study subjects offer a rare and unique glimpse into the

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<v Speaker 1>potential for long term genetic changes in space, the researchers

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<v Speaker 1>are quick to admit that their tiny sample size means

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<v Speaker 1>more testing is essential. With only two study subjects, they

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<v Speaker 1>can't be sure that any changes are due to space travel.

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<v Speaker 1>More research with other astronauts needs to be done. The

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<v Speaker 1>methodology for the study involved collecting blood samples, physiological data,

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<v Speaker 1>and cognitive measurements from each Kelly twin at various points

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<v Speaker 1>over twenty seven month period before, during, and after Scott's

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<v Speaker 1>one year space mission. If you're wondering how in the

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<v Speaker 1>world or universe scott samples reached the scientists from space,

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<v Speaker 1>they were transported via rockets. In the future, scientists hope

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<v Speaker 1>to process and store samples on board the International Space

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<v Speaker 1>Station itself, but for the parts of this study, samples

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<v Speaker 1>were rocketed back to Earth and processed within forty eight hours.

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<v Speaker 1>Then the research team examined the Brothers genomes, looking for

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<v Speaker 1>epigenetic changes, specifically focusing on two types of white blood

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<v Speaker 1>cells and examining a process called methylation, which occurs when

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<v Speaker 1>chemical compounds called methyl groups are added on too d NA.

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<v Speaker 1>Generally speaking, there were just about as many epigenetic changes

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<v Speaker 1>in Scott as there were in his twin. The biggest

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<v Speaker 1>difference was observed nine months into Scott's space mission, when

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<v Speaker 1>just sev of his DNA was methylated compared to th

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<v Speaker 1>of marks DNA. The locations of methylation were different in

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<v Speaker 1>both men. Scott's methylation appeared near genes involved with immune

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<v Speaker 1>system response, which the researchers believe correlates with additional data

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<v Speaker 1>that found that Scott had increased markers associated with inflammation,

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<v Speaker 1>which is a potential red flag, but again bears further

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<v Speaker 1>study to determine whether this difference was really caused by

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<v Speaker 1>Scott's location in space. Oh though, one other weird thing

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<v Speaker 1>that definitely did happen to Scott in space. The shape

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<v Speaker 1>of one of his eyeballs changed. By the time he

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<v Speaker 1>got back to Earth, his retinal nerve and the folds

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<v Speaker 1>in the layer that surround the eye were thicker. Researchers

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<v Speaker 1>think this could have to do with prolonged exposure to

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<v Speaker 1>low gravity, another thing to watch out for in the

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<v Speaker 1>future for sure. Today's episode was written by Michelle Konstantinovski

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<v Speaker 1>and produced by Tyler Clang. Brain Stuff is a production

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<v Speaker 1>of iHeart Radio's How Stuff Works. For more in this

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<v Speaker 1>and lots of other stories that involved not entirely unexpected rockets,

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<v Speaker 1>visit our home planet, how stuff works dot com For

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