National Aeronautics and Space Administration (NASA) Astronaut Scott Kelly recently returned to Earth after spending a full year in space in an unprecedented NASA mission entitled “A Year In Space” to ascertain whether or not humankind’s prospects of inhabiting Mars could ever be attained in the near future. Along with setting the world record for the “most consecutive days spent in orbit”, NASA studies have revealed that 7% of Kelly’s deoxyribonucleic acid (DNA) no longer matches that of his identical twin, astronaut Mark Kelly, who remained on Earth during the entirety of the mission.

Scientists have deduced the genetic fluctuations to derive from the circulation of the blood’s cell-free DNA, or changes in the gene’s epigenome or telomeres, which determines the genes being expressed as well as the chromosomes’ aging processes through reduction and expansion. Although these unique mutations have been about 93% temporary and have vanished within 48 hours of Kelly’s return to Earth, about 7% of Kelly’s genes pertaining to the “immune system, DNA repair, bone formation networks, hypoxia, and hypercapnia” have remained erratic, according to CNN. Specifically, Kelly’s body had amplified and reduced the expression of some genes at the expense of others to adjust to the conditions of space and microgravity.

However, NASA ascribed the DNA alteration to be expected and normal as it was simply due to the body’s reaction to the surrounding environment. In fact, scientists believe that an increase of stress is a likely cause of the gene expression change. In a statement released by the NASA agency, it confirms that “Mark and Scott Kelly are still identical twins” because “Scott’s DNA did not fundamentally change”, and that even identical twins do not have perfectly identical genomes.

These conclusions have since been thoroughly investigated in NASA’s “Twins Study”, and have been part of a larger discussion of the relationship between space flight and the body’s molecular level. While results are still inconclusive, NASA assures that the consequences of the gene expression are minimal and that further research will be conducted in the summer.

In one of the most peculiar scientific studies, this groundbreaking study has broad implications and extends far beyond the Kelly brothers. As for the future, because of the potentially dangerous consequences of extended space travel on astronauts’ genes and health, NASA will have to administer further experimentation to ensure that the prospective three-year long trip to Mars, dubbed the “Red Planet” Mission, will be safe to attempt.