Without realizing it, humans might be able to innately detect Earth’s magnetic field, thanks to a compound found in our eyes. Or we may have been able to do so some time in the past.
Plenty of animals are known to be able to perceive geomagnetism, using it to navigate and even to hunt their prey. Proteins called cryptochromes, which exist throughout the plant and animal kingdoms, lend several species this ability. The proteins are related to the circadian rhythms of animals and plants, and recent studies have shown it apparently enables light to serve as a geomagnetic locator.
Electrons in cryptochrome molecules come in entangled pairs, and the Earth's magnetic field may cause one of the electrons to wobble. A chemical reaction in response to the wayward electron's altered spin lets birds see magnetic fields in color, according to a theory published last summer.But as far as researchers thought, cryptochrome doesn’t do much to help us orient ourselves, hence why people have to rely on celestial objects, known landmarks and GPS to figure out which way is north.
But a new study suggests the protein could actually express itself in the retina to help detect geomagnetism. Neuroscientists at the University of Massachusetts took a human version of cryptochrome 2, and inserted it into fruit flies that lacked their own version. The fruit flies’ magnetic perception was restored, as Wired Science reports.
It may not work this way anymore — there are not exactly voluminous reports of humans navigating simply by peering at magnetic field lines — but it could have proved valuable in helping our earliest ancestors navigate, according to researchers who spoke to Wired. Maybe someday researchers will figure out how to exploit this ability once again, and you won’t need that GPS function in your smartphone after all.
The study is reported in today’s issue of Nature Communications.