People may be able to 'see' magnetic fields just as migrating birds do - or, at any rate, have once had the ability to do so in the past.
New research from the University of Massachusetts Medical School has shown that a protein expressed in the human retina, CRY2, can sense magnetic fields when implanted into Drosophila.
In many migratory animals, such as birds and sea turtles, the ability to sense the earth's magnetic field has been linked to light-sensitive chemical reactions involving the flavoprotein cryptochrome (CRY).
Previous work by the team had already established that, in the fruit fly Drosophila, the cryptochrome protein found in their retinas could function as a light-dependent magnetic sensor.
To test whether the human cryptochrome 2 protein (hCRY2) could do the same thing, professor Steven Reppert and post-doctoral fellow Robert Gegear created a transgenic Drosophila model that had the human version rather than its own.
And they found that the flies were still able to sense and respond to a magnetic field generated by an electric coil, in the same light-dependent way.
While human beings clearly aren't consciously aware of magnetic fields, the results do imply that we're sensing them at some level all the same. Reppert and his team say they'd like to carry out more research.