Animals make proteins called cryptochromes that, in creatures such as migratory birds, are thought to enable sensing of Earth's magnetic field for navigation. Now researchers show that human cryptochrome may be sensitive to magnetic fields.

Steven Reppert at the University of Massachusetts Medical School in Worcester and his colleagues replaced the cryptochrome gene of the fruitfly Drosophila with a human version. They then placed the fruitflies in a two-armed maze in which one arm was magnetized, and compared the number of flies in each arm as a measure of their ability to sense the magnetic field.

Drosophila bearing the human cryptochrome gene responded to the magnetic field in the same way as normal flies, by avoiding the field, and the response required blue light. The authors suggest that the protein can, at least at the molecular level, function as a magnetosensor.

Nature Commun. doi:10.1038/ncomms1364 (2011)