SSS 2011-06-23

（单词翻译）

This is Scientific American's 60-Second Science. I'm Christopher Intagliata. Got a minute?

Birds and sea turtles can migrate thousands of miles, by reading the Earth's magnetic cues. But we too might have magnetic sensing abilities—in our eyes. So says a study in the journal Nature Communications.

Previous studies suggest long-distance migrators—and even fruit flies—pick up magnetic fields with the help of a light-sensitive protein called "cryptochrome." We produce cryptochrome too—without it, our circadian clocks would break. Human cryptochrome doesn't require light to function, though—and it doesn't seem to give us a phenomenal sensitivity to magnetic fields. But can it do more than keep the circadian clock ticking?

To find out, researchers took out fruit flies' usual cryptochrome gene¹ and inserted the human version. And the transgenic flies had no problem navigating² a magnetic maze³ when exposed to light—indicating the human protein can still serve as a light-sensitive magnetic sensor⁴.

We happen to have a lot of cryptochrome in our retinas—ideally situated⁵ 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 don't throw away your GPS.

Thanks for the minute. For Scientific American's 60-Second Science, I'm Christopher Intagliata.