Humans may have a sixth sense after all, suggests a new USENET newsgroup post on biology newsgroups that include a study finding that a protein in the human retina, when placed into fruit flies, has the ability to detect magnetic fields.
The researchers caution that the results suggest this human protein has the capability to work as a magnetic sensor; however, whether or not humans use it in that way is not known.
University of Massachusetts in Worcester researcher and colleagues study cryptochromes – light-sensitive proteins that regulate the circadian clocks of many creatures. Steve Reppert, head researcher, knew that cryptochromes also help fruit flies and birds sense the Earth’s magnetic fields, and he wanted to see whether human cryptochromes could do the same thing. To find out Reppert replaced those found in fruit flies with a human version, hCRY2, which is found in the retina.
The mutant flies were trained to associate a sugar reward with a magnetic field. When given the option to fly down either a magnetized or non-magnetized arm of a maze they opted for the magnetized one. Flies genetically engineered to lack cryptochrome altogether were indifferent to the magnetic field in one arm and were evenly distributed down both arms of the maze. Apparently, fruit flies have no problem using human cryptochrome to sense magnetic fields, which implies humans have the hardware to do the same, but for some reason do not activate the ability, says Reppert.
The experiments show that CRY2, a human eye protein, can act as a magnetic sensor. But only out of its native environment. In its native environment, CRY2 undoubtedly acts differently, due partially to the fact that it is only one component needed for an internal navigation system. To successfully detect magnetic fields an organism requires an apparatus that processes changes in the cryptochrome, and communicate those changes to the brain. Drosophila obviously has such an apparatus, but whether humans do is doubtful.
These findings demonstrate that hCRY2 has the molecular capability to function in a magnetic sensing system and may pave the way for further investigation into human magneto reception. “Additional research on magneto sensitivity in humans at the behavioral level, with particular emphasis on the influence of magnetic field on visual function, rather than non-visual navigation, would be informative,” wrote Reppert and his colleagues in the study.