You know those eyes in the back of you're head you've always wanted? Geneticists have now figured out how to get tadpole embryos to grow any organ, anywhere in their bodies.
When an embryo is developing, it somehow just knows where to put eyes and hands and brains and pancreases and appendices and stuff. Vertebrates (whether they're tadpoles or humans) are complicated creatures, and if you get organs in the wrong place, things generally don't work as well. Biologists at Tufts University have figured out that organ placement is controlled by slight differences the electrical properties of the cells themselves, which cause the genetic code for building different organs to turn on and off.
By artificially tweaking the voltages of cell membranes, the researchers were able to fool cells in the back and tail of a tadpole embryo into thinking that they were actually where an eye needed to be. So, they went and turned themselves into an eye. On the tadpole's back. And tail. And the eyes worked. The really amazing part (since having working tail-eyes isn't amazing enough) is that cells in these areas were thought to be unable to form eyes, but as it turns out, they're happy to do it, as long as you can convince them that it's what they're supposed to be doing.
So what can we do with this? The researchers, of course, aren't talking about giving us extra eyeballs. At least, not in public. What they are talking about is regenerative medicine, like growing another limb if you lose one, and forming new organs from scratch for transplantation.
Via Science Daily