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　　Birds and sea turtles can migrate thousands of miles， by reading the Earths magnetic cues. But we too might have magnetic sensing abilitiesin our eyes. So says a study in the journal Nature Communications. [Lauren Foley， Robert Gegear and Steven Reppert， Human Cryptochrome Exhibits Light-Dependent Magnetosensitivity]

　　Previous studies suggest long-distance migratorsand even fruit fliespick up magnetic fields with the help of a light-sensitive protein called cryptochrome. We produce cryptochrome toowithout it， our circadian clocks would break. Human cryptochrome doesnt require light to function， thoughand it doesnt seem to give us a phenomenal sensitivity to magnetic fields. But can it do more than keep the circadian clock ticking?考试大考试大成就你的梦想

　　To find out， researchers took out fruit flies usual cryptochrome gene and inserted the human version. And the transgenic flies had no problem navigating a magnetic maze when exposed to lightindicating the human protein can still serve as a light-sensitive magnetic sensor.

　　We happen to have a lot of cryptochrome in our retinasideally situated to receive light. Which suggests we might be able to see magnetic fields in some way. On the other hand， evolution might have just given cryptochrome a new job in new organisms. So dont throw away your GPS.