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Speaker 1: Welcome to brain Stuff, a production of I Heart Radio. Hey,

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Speaker 1: brain Stuff, Lauren Boglebam here. Have you ever wondered exactly

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Speaker 1: what happens to the human body when it's suspended in

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Speaker 1: space for an extended period of time? Based on Hollywood

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Speaker 1: productions alone, men and women who navigate the galaxy always

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Speaker 1: seemed to be just fine when they land back on Earth.

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Speaker 1: But are astronauts so lucky in reality? NASA has made

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Speaker 1: it its mission to find out. In a landmark DNA

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Speaker 1: study published in April nineteen issue of the journal Science,

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Speaker 1: researchers from John Hopkins, Stanford and other institutions revealed after

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Speaker 1: a year in space, astronauts Scott Kelly experienced no major

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Speaker 1: long term differences to his epigenome compared with that of

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Speaker 1: his twin brother, current Arizona Senate candidate Mark Kelly, who

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Speaker 1: stayed firmly planted here on Earth. Your epigenome is all

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Speaker 1: of the chemical compounds that have attached to your DNA

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Speaker 1: and changed the way it functions, so no major differences

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Speaker 1: is hypothetically a good thing. Here's the deal with putting

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Speaker 1: your body in space. It exposes you to harmful ultra

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Speaker 1: violet rays radiation, limited food and exercise, lower gravity, disrupted

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Speaker 1: sleep cycles, and an unknown number of other potential hazards.

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Speaker 1: And while scientists have spent decades studying the effects of

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Speaker 1: space travel on astronauts, most of these men and women

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Speaker 1: have traveled on missions that macks out at six months.

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Speaker 1: In order to travel somewhere like say Mars, missions need

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Speaker 1: to be much longer, and scientists say it's critical to

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Speaker 1: understand the effects that these super extended missions could have

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Speaker 1: on the human body. Let's talk more about how your

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Speaker 1: epigenome works. Your DNA is your genome. It's the genetic

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Speaker 1: code that tells every cell in your body how to

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Speaker 1: build different proteins, which determines how those cells function. Your

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Speaker 1: epi genome is any chemical modifications to your d NA.

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Speaker 1: These modifications don't change your actual DNA sequence, but they

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Speaker 1: can change how your cells use the instructions that your

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Speaker 1: DNA gives them. So these tiny chemical alterations can have

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Speaker 1: a major impact on a person's health by influencing the

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Speaker 1: way their genes are expressed. They can switch genes from

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Speaker 1: on to off, and vice versa. A major advantage of

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Speaker 1: this new research is the fact that it studies identical

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Speaker 1: twins who naturally have identical genetic material. But while the

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Speaker 1: study subjects offer a rare and unique glimpse into the

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Speaker 1: potential for long term genetic changes in space, the researchers

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Speaker 1: are quick to admit that their tiny sample size means

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Speaker 1: more testing is essential. With only two study subjects, they

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

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Speaker 1: More research with other astronauts needs to be done. The

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Speaker 1: methodology for the study involved collecting blood samples, physiological data,

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Speaker 1: and cognitive measurements from each Kelly twin at various points

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Speaker 1: over twenty seven month period before, during, and after Scott's

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Speaker 1: one year space mission. If you're wondering how in the

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Speaker 1: world or universe scott samples reached the scientists from space,

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Speaker 1: they were transported via rockets. In the future, scientists hope

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Speaker 1: to process and store samples on board the International Space

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Speaker 1: Station itself, but for the parts of this study, samples

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Speaker 1: were rocketed back to Earth and processed within forty eight hours.

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Speaker 1: Then the research team examined the Brothers genomes, looking for

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Speaker 1: epigenetic changes, specifically focusing on two types of white blood

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Speaker 1: cells and examining a process called methylation, which occurs when

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Speaker 1: chemical compounds called methyl groups are added on too d NA.

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Speaker 1: Generally speaking, there were just about as many epigenetic changes

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Speaker 1: in Scott as there were in his twin. The biggest

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Speaker 1: difference was observed nine months into Scott's space mission, when

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Speaker 1: just sev of his DNA was methylated compared to th

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Speaker 1: of marks DNA. The locations of methylation were different in

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Speaker 1: both men. Scott's methylation appeared near genes involved with immune

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Speaker 1: system response, which the researchers believe correlates with additional data

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Speaker 1: that found that Scott had increased markers associated with inflammation,

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Speaker 1: which is a potential red flag, but again bears further

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Speaker 1: study to determine whether this difference was really caused by

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

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Speaker 1: that definitely did happen to Scott in space. The shape

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Speaker 1: of one of his eyeballs changed. By the time he

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Speaker 1: got back to Earth, his retinal nerve and the folds

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Speaker 1: in the layer that surround the eye were thicker. Researchers

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Speaker 1: think this could have to do with prolonged exposure to

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Speaker 1: low gravity, another thing to watch out for in the

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Speaker 1: future for sure. Today's episode was written by Michelle Konstantinovski

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Speaker 1: and produced by Tyler Clang. Brain Stuff is a production

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Speaker 1: of iHeart Radio's How Stuff Works. For more in this

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Speaker 1: and lots of other stories that involved not entirely unexpected rockets,

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Speaker 1: visit our home planet, how stuff works dot com For

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Speaker 1: more podcasts. For my heart Radio, visit the iHeart Radio app,

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Speaker 1: Apple Podcasts, or wherever you listen to your favorite shows.