NASA's twin astronaut experiment

NASA brought one of the twin brothers into space to compare the changes in their bodies.

NASA astronaut Scott Kelly returned to Earth after spending 340 days in space in March 2016, according to Independent. When Scott lived on the International Space Station (ISS), scientists also observed Scott's twin brother, Mark Kelly, on a normal life on Earth. Their goal is to study changes in the human body when making a flight into space.

Scott and Mark are perfect subjects to conduct experiments because they have the same DNA. This means that scientists have a rare chance to directly compare the gene changes of Scott and Mark over the same time period.

Astronaut Scott Kelly (right) stood with his twin brother Mark Kelly on January 19, 2015.(Photo: NASA).

Astronauts living in a zero gravity environment for about 6 months or less may suffer negative effects on the body such as spinal relaxation, muscle contraction or sleep cycle disorders. However, the effect of long-term exposure to space is less known.

Researchers took biological samples of both twins before, during and after Scott's mission on ISS. Research results of twins are announced by NASA at the end of January 2017. This data will help a lot for future deep space missions.

When Scott was in the universe, telomeres (protective caps at the end of the chromosome, affecting aging and disease) became longer than their twin, but quickly shrank as size. normal when returning to Earth.

The level of DNA methylation in Scott's white blood cells decreased during the space trip. The level of methylation is the process of changing the activity of a piece of DNA without changing its nucleotide sequence. By analyzing RNA in the white blood cells of the two brothers, the scientists found they had about 200,000 different RNA molecules.

During the study, Scott and Mark had different intestinal bacteria, or digestive support bacteria . This may be due to their different diet and living environment, according to NASA.