As the old joke goes: three fish are in a tank, one says “How do you drive this thing?” Medaka fish like these have gone one better – blasting off on a space rocket. On board the International Space Station (ISS), medaka make good models for the effects of low gravity on humans. Recently, scientists in Japan watched remotely from Earth as a microscope on the ISS took a close look at developing medaka bone cells. Within a day of being in microgravity, genes in the fish’s osteoblast and osteoclast cells, which help to make new bones, began to change. This strange bone-building response may combat the loss bone minerals brought on by low gravity, suggesting clues to why human astronauts often have skeletal problems. Future space-travellers may have these pioneering gravitational biology experiments, and the medaka fish, to thank for pain-free missions in the future.
Written by John Ankers
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