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Re: Shaking up the bird family tree



Well, if we consider that we could induce teeth formation in chicken
beak, loss and regain of complex character do not seem to be so
impossible.

True, but the switching of teeth is largely a regulation change. Tooth formation can be switched on with little trouble, because the rest of the developmental pathway is still intact. Even then, the teeth are small and fairly non-functional.


In avian wing reduction, by contrast, we tend to see a more complex reduction in several continuous characters (forelimb skeletal characters, flight feather production, sternal complex robustness, pectoralis mass, etc). Simple up-regulation changes are unlikely to re-induce full flighted ability in neoflightless birds.

Still, we shouldn't consider it impossible, just complicated.

Cheers,

--Mike


Michael Habib, M.S. PhD. Candidate Center for Functional Anatomy and Evolution Johns Hopkins School of Medicine 1830 E. Monument Street Baltimore, MD 21205 (443) 280 0181 habib@jhmi.edu