AS RARE AS HEN’S TEETH
This is pretty cool:
Working late in the developmental biology lab one night, Matthew Harris of the University of Wisconsin noticed that the beak of a mutant chicken embryo he was examining had fallen off. Upon closer examination of the snubbed beak, he found tiny bumps and protuberances along its edge that looked like teeth–alligator teeth to be specific. The accidental discovery revealed that chickens retain the ability to grow teeth, even though birds lost this feature long ago… The mutant chickens Harris studied bear a recessive trait dubbed talpid2. This trait is lethal, meaning that such mutants are never born, but some incubate in eggs as long as 18 days. During that time, the same two tissues from which teeth develop in mammals come together in the jaw of the mutant embryo–and this leads to nascent teeth, a structure birds have lacked for at least 70 million years. “They don’t make a molar,” explains development biologist John Fallon, who oversaw Harris’s work. “What they make is this conical, saber-shaped structure that is clearly a tooth. The other animal that has a tooth like that is an alligator.”
Yes, evolution and common descent really are a wonderful theory. (via The Panda’s Thumb)