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Scott Kelly’s Time In Space Made Him a Genetic Mutant? Not So Fast.
Let’s rein in the hype and think critically for a moment
Several media outlets have jumped on the story that astronaut Scott Kelly’s DNA was “changed” by his time in space. One article I saw even claimed that these findings could undermine Elon Musk’s plans for Mars exploration and long-term space missions.
But let’s take a step back and do some critical analysis.
First, according to NASA itself, Scott’s DNA didn’t change per se. That is, his gene expression pattern changed, which is quite different than a change in the sequence of the nucleotide base pairs that make up DNA. This is really a type of epigenetic phenomenon.
Epigenetics has to do with the way strings of DNA fold and bend so that the molecular machinery that changes the DNA into proteins works a little differently. Basically, epigenetic events can increase or decrease the rate at which DNA is changed into proteins, and thus modulate the effect of genes on physiology.
Studies that compare identical twins have clearly shown that twins can turn out quite differently due to epigenetic changes, despite having the same DNA sequence. The differences arise from differences in environment.
