Does Space Travel Change You? NASA Sent One Identical Twin Brother to Space and Finds Out

NASA sent one identical twin brother, Scott, to space, to study the biological differences between him and his brother, Mark, who remained on Earth. Scott returned to Earth last March, and researchers have found some interesting results.

In a study to find out how space travel biologically affects you, NASA sent one identical twin brother, Scott, to space, while the other, Mark, remained on Earth. They then compared their biological samples, and have found some interesting results. It will still be some more time before the full results are out.

The Study

Identical twin studies are often a good way to understand the external effect of something, as both twins have identical DNA.

NASA used this rare opportunity to send Scott to space for 340 days aboard the International Space Station. Scientists were regularly observing Scott as well as Mark on Earth throughout the study.

Scientists already knew that living in a weightless environment for six months or less could have negative effects on the body.

For example, the spine stretches, muscles shrink and sleeping patterns are disrupted. However, this study focused on long-term effects, which remain unknown.

The Results

The results from the study were published in late January. However, further results will still come out as researchers continue to comb through the data from biological samples before, during and after the space mission.

Some of the results were:

  • Scott’s telomeres got longer and then went back to normal on Earth
    • This was exactly the opposite of what scientists expected, since shorter telomeres are associated with older age. NASA says this could be due to eating less and exercising more, but they remain unsure.
  • Scott’s methylation levels decreased
    • Methylation of DNA is a way DNA expression could be changed without actually changing the DNA code itself. Scott’s white blood cells’ methylation decreased while Mark’s increased half way through the mission. NASA says: “These results could indicate genes that are more sensitive to a changing environment, whether on Earth or in space.”
  • Scientists looked for a “space gene”
    • Scientists sequenced the RNA from Scott and Mark’s white blood cells and found over 200,000 RNA molecules that were expressed differently between them. Twins do often have unique mutations, but scientists are looking to see if any of these differences were due to space travel.
  • The twins had different gut bacteria
    • The bacteria that aid the digestive system were different throughout the year and different between both twins. This could be due to different diets and environments.
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