Researchers grafted the tails of blind tadpoles of the African frog with eye tissue, which gave the tadpoles sight.
CREDIT: Douglas Blackiston


Whoa! Mutant Tadpoles Sprout Eyeballs on Their Tails

Charles Choi, LiveScience Contributor
Date: 27 February 2013 Time: 06:01 PM ET

Eyes hooked up to the tail can help blinded tadpoles see, researchers say.

These findings could help guide therapies involving natural or artificial implants, scientists added.

A major roadblock when it comes to treating blindness and other sensory disorders is how much remains unknown about the nervous system and its ability to adapt to change. To learn more about the relationship between the body and the brain, researchers wanted to see how capable the brain was of interpreting sensory data from abnormal “ectopic” locations from which it normally does not receive signals.

Eye on the tail

Scientists experimented with 134 tadpoles of the African clawed frog Xenopus laevis, a common lab animal. They painstakingly grafted new eyes onto places such as their torsos and tails and then surgically removed their original eyes.

“We do a lot of work to understand regenerative biology, and that entails experiments that change the body,” researcher Michael Levin, a developmental biologist at Tufts University, told LiveScience. “We have four-headed worms, six-legged frogs, and many other unusual creatures here as part of our work on bioelectricity and organ regeneration.”

These experimental tadpoles then received a vision test the researchers first refined on normal tadpoles. The tadpoles were placed in a circular arena half illuminated with red light and half with blue light, with software regularly switching what color light the areas received. When tadpoles entered places lit by red light, they received a tiny electric zap. A motion-tracking camera kept tabs on where the tadpoles were.

Remarkably, the scientists found that six tadpoles that had eyes implanted in their tails could apparently see, choosing to remain in the safer blue-light areas.

Read more: Whoa! Mutant Tadpoles Sprout Eyeballs on Their Tails | Weird Animal News | LiveScience.

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