Chickens Grow ‘Dinosaur Legs’

By Nathaniel Scharping | March 15, 2016 2:37 pm
Silly chook trying to balance on a curved chair back. Chickens are total clutzes.

(Credit: ap./Flickr)

It may not be Jurassic Park, but it’s certainly a step in that direction.

Scientists from the University of Chile have successfully created chicken embryos with a unique feature: dinosaur legs. Don’t imagine chickens stomping around with giant Brontosaur legs, though — the changes are all internal.

The feature in question is the fibula, one of two bones inside the leg. In normal birds, the fibula stops about halfway down the leg, connected at the top but not the bottom, leaving it just hanging in space.

Bone Stops Growing

When chicken embryos form, they have a full fibula, but as they grow, the fibula stops growing along with them. Instead, it separates from the ankle where it was first attached and grows thinner and more spindle-like. Dinosaurs, like humans, had full fibulas to help support their massive weight. It seems that, at some point in their evolution, birds stopped needing the extra bone.

By modifying one gene, however, the researchers were able to undo the change. When they inhibited the expression of the Indian Hedgehog (IHH) gene, all the chicken embryos kept their fibulas throughout their development. They believe it has something to do with a bone in the ankle called the calcaneum, which normally connects to the fibula. When the IHH gene was suppressed, the calcaneum began to produce the parathyroid-related protein (PthrP) gene, responsible for promoting bone growth.

With the gene modification, the chickens’ fibulas kept growing throughout their development, as opposed to stopping halfway. The researchers discovered that, in normal birds, the cartilaginous growth plates at the end of their fibulas disappear shortly after they form, effectively halting bone growth. But with one small modification, millions of years of evolution can be undone. They published their work in the journal Evolution.

shutterstock_81528802 (1)

Developing chicken embryo. (Credit: Anneka/Shutterstock)

Working Backward

Genetic experiments of this kind have goals far more scientific than the creation of a theme park filled with once-extinct reptiles. By selectively altering specific genes in birds, researchers can essentially de-evolve them to see how they attained their current forms over millions of years. The same team of researchers succeeded in creating chickens with dinosaur-like feet last year, and a separate team in the U.S. led by famed paleontologist Jack Horner grew dinosaur beaks on chickens. All three experiments have a similar goal: to find the genetic roots of avian evolution.

The chickens grown in the lab did not hatch, but matching a key feature of the evolution of birds from dinosaurs to a single gene highlights the fact that echoes of the dinosaurs remain in the DNA of birds today.

Whether we choose to use that knowledge for good or evil remains up to us.

MORE ABOUT: evolution
  • D Ash

    Oh, those poor chickens! Put ’em on my grill! I’ll save ’em!

  • Mike Richardson

    Actually, Horner has discussed going further to reverse engineer dinosaurs from birds (or at least as close as we could get to a small therapod), and even wrote a book on the subject. That might not be the best thing, considering the right mix of modern bird genes could give you something the size of an ostrich, possibly with the brains of an African grey parrot or crow (or on the other spectrum, a turkey), but with sharp claws and teeth. We’ve all seen how that works out in the Jurassic Park movies.

    • Pat Gunn

      Pretty well – at least the first movie was rather profitable.
      On the off chance you’re talking about the content of the movies, it’s ridiculous to use works of fiction as a basis for understanding what would happen in reality.

      • Mike Richardson

        Only in the broadest sense, in that you really can’t predict how such animals might behave, and the possibility that creatures resembling predatory animals might obviously prove dangerous to people. Btw, the last movie was pretty profitable too, and also raised the specter of using such chimeras as biological weapons, which might be more realistic (and depressing) than the idea of live amusement park attractions.

  • iq145

    What? Something this incredible, yet no photos?

    • Sanne

      They said the chickens grown in the lab didn’t hatch, so that’s probably why.



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