The Great Debate – Drumstick or Wing?

Scientists, it seems, have decidedly taken sides with the drumstick lovers and have created a chook with three legs.

They have been working on trying to unravel the genetic sequence of limb development, that is – why is a leg a leg and not a wing? They focused on three genes in particular. Normally, Tbx5 is turned on in the wing, and Tbx4 and Pitx1 are turned on in the leg.

To determine the gene responsible for leg development the scientists stuck Pitx1 into a virus, then sprayed the virus on the would-be wing nub of a chick embryo. Amazingly, the resulting chicken had 3 legs and just one lonely wing!

However, the third leg isn’t a perfect drumstick. While feathers became scales, and the limb was straight, clawed and muscled like a leg, some wing characteristics still remained.

This means that Pitx1, while switching on the ‘leg gene’ (Tbx4) in the wing, had no effect on the actual ‘wing gene’ (Tbx5), being independent of it. Both were switched on, making the limb a wing-leg hybrid. More bizarrely, Japanese researchers have now achieved a complete wing and leg position interchange.

While these odd chooks have caused egg-citement in chook farmers and KFC lovers alike, their creation had a more noble purpose. Scientists believe that by understanding the genes responsible for forelimb and hindlimb development, they could one day be able to correct or prevent limb deformities in humans.

Really though, my vote is for the four winged chook. Less meaty, a little less able to walk, but altogether a major step back towards that airy domain, so that they may fulfill their ancestry and return to their rightful place as lords of the sky.

by Stephanie Clark

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