Exploring NASA’s ‘Twin Study,’ and What It Says About Our DNA in Space

Expedition 45/46 Commander, Astronaut Scott Kelly along with his brother, former Astronaut Mark Kelly speak to news media outlets about Scott Kelly’s one-year mission aboard the International Space Station (Robert Markowitz/NASA)

A year ago, twin astronauts Scott and Mark Kelly agreed to take part in a groundbreaking study (which NASA calls “The Twin Study”), testing the effects of space travel on human DNA. Some of the test results have been processed, and they reveal some unexpected genetic changes.

Due to the brothers’ almost identical genomes and similar life experiences, they were ideal subjects for this experiment, which required Scott to spend nearly a consecutive year in space; with measurements of his gene expression and other biological markers taken before, during, and after his mission. His brother Mark remained on Earth.

NASA astronaut Scott Kelly performs the Fine Motor Skills Test as part of his One-Year Mission. This task tests Kelly’s ability to use his fine motor skills – pointing, dragging, shape tracing, and pinch-rotate – on an Apple iPad after extended time in space. (NASA)

Although these are early test results—that may not be generalizable to other space travelers—researchers were surprised to find that Scott’s telomeres, the caps on the ends of chromosomes, grew longer while he was in orbit. Since telomeres generally shrink over the course of a lifetime, and the stresses of spaceflight were thought to accelerate that process, these results threw NASA for a loop.

It’s also worth noting that telomere lengthening has been linked to some disease processes and pathologies, hence the researchers’ concern. Thankfully, Scott’s telomeres shrank back to normal once he returned to Earth.

In this September 24, 2015, photo made available by NASA, astronaut Scott Kelly gives himself a flu shot aboard the International Space Station for an ongoing study on the human immune system. The vaccination is part of NASA’s Twins Study, a compilation of multiple investigations that take advantage of a unique opportunity to study identical twin astronauts Scott and Mark Kelly, while Scott spends a year aboard the station and Mark remains on Earth. (NASA via AP)

AP

The researchers also found a decrease in Scott’s DNA methylation, which is the process by which our genes deactivate sections that don’t need to be copied. By contrast, Mark’s DNA methylation increased over that period of time on Earth.

The full results are still being processed, but information about how space travel affects molecular change within the body is useful for refining pre-flight medical testing and screening, and for predicting how the human body will react to prolonged time in space (like, say, flights to Mars).

—RealClearLife Staff