Chicken that bites back

Matthew Harris didn't flinch at the crocodilian-like teeth flashing six inches in front of his face. He didn't scream or whimper, either.

Instead, he sat back, shook his head and leaned in for a better look.

That's because Harris, a researcher at the University of Wisconsin-Madison last year, wasn't looking into the mouth of a giant, dentition-ridden reptile.

He was looking into the mouth of a chicken.

Harris, who is now at a research institute in Germany, and a team of researchers from Madison and the University of Manchester in England have discovered teeth in a mutant line of chickens.

And their discovery supports the premise that ancient genetic signals can be resurrected - remaining dormant or not expressed in an organism's DNA - for millions of years, waiting for the right conditions to spark their return.

This is a phenomenon known to developmental biologists and geneticists as atavism, popularly called "throwbacks."

The discovery also sheds light on the molecular and developmental mechanisms behind tooth loss and beak growth in birds, giving paleontologists a bird's-eye view of the biological processes that took place millions of years ago, as one line of a raptor-like dinosaur crossed the taxonomic boundary from reptile to bird.

The paper appears in this week's issue of Current Biology.

"Throwbacks?" "Atavism?"

Could this explain a few things about certain members of the Burri clan?