Space does weird things to the human body.
From leaving you uncoordinated after months spent in weightlessness to atrophied muscles, space travel can wreak havoc on you physically.
But growing another head? That's a new one.
According to a new study published in the journal Regeneration, an amputated piece of a flatworm (D. japonica) grew two heads during its five weeks on the International Space Station.
On Earth, this is very rare kind of mutation for these varieties of worms, which are typically less than half an inch long and can regenerate from amputated segments.
"In more than 18 person-years of maintaining a colony of D. japonica that involves more than 15,000 control worms in just the last five years alone, the Tufts researchers have never observed a spontaneous occurrence of double-headedness," a Tufts University news release states.
"Moreover, when the researchers amputated both heads from the space-exposed worm, the headless middle fragment regenerated into a double-headed worm, demonstrating that the body plan modification that occurred in the worm was permanent."
Some of the 15 flatworms sent to space aboard a SpaceX Dragon cargo craft in 2015 also spontaneously split into two or more identical pieces in a process called fission, even though the control samples maintained on the ground didn't go through that same process.
Also, when they came back to the planet, the worms that lived in space spent less time in the dark than the control group, and they were partially paralysed before returning to normal a couple hours later, according to the statement.
The differences in the space-exploring flatworms and their control counterparts on the ground may not be entirely explained by spaceflight.
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