Quick – can you tell where north is? Animals as diverse as sea turtles, birds, worms, butterflies and wolves can, thanks to sensing Earth’s magnetic field.
But the magnet-sensing structures inside their cells that allow them to do this have evaded scientists – until now.
A team led by Can Xie’s at Peking University in China has now found a protein in fruit flies, butterflies and pigeons that they believe to be responsible for this magnetic sense.
“It’s provocative and potentially groundbreaking,” says neurobiologist Steven Reppert of the University of Massachusetts who was not involved in the work. “It took my breath away.”
There used to be two competing theories about magnetic sense: some thought it came from iron-binding molecules, others thought it came from a protein called cryptochrome, which senses light and has been linked to magnetic sense in birds.
Xie’s group was the first to guess these two were part of the same system, and has now figured out how they fit together.
“This was a very creative approach,” says Reppert. “Everyone thought they were two separate systems.”