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Re: Birds Have Dinosaur Wings: The Molecular Evidence

No problema, here go... :)

Birds Have Dinosaur Wings: The Molecular Evidence

J. Exp. Zool. (Mol. Dev. Evol.) 304:000­000, 2004. Early View


Within developmental biology, the digits of the wing of birds are
considered on embryological grounds to be digits 2, 3 and 4. In
contrast, within paleontology, wing digits are named 1, 2, 3 as a
result of phylogenetic analysis of fossil taxa indicating that birds
descended from theropod dinosaurs that had lost digits 4 and 5. It
has been argued that the development of the wing does not support the
conclusion that birds are theropods, and that birds must have
descended from ancestors that had lost digits 1 and 5. Here we use
highly conserved gene expression patterns in the developing
limbs of mouse and chicken, including the chicken talpid2 mutant and
polydactylous Silkie breed (Silkie mutant), to aid the assessment of
digital identity in the wing. Digit 1 in developing limbs does
not express Hoxd12, but expresses Hoxd13. All other digits express
both Hoxd12 and Hoxd13. We found this signature expression pattern
identifies the anteriormost digit of the wing as digit 1, in
accordance with the hypothesis these digits are 1, 2 and 3, as in
theropod dinosaurs. Our evidence contradicts the long-standing
argument that the development of the wing does not support the
hypothesis that birds are living dinosaurs.

El Viernes, 5 noviembre, 2004, a las 06:26 PM, Amtoine Grant escribió:

Umm, does anybody have this in English? I'm not too fluent in spanish & i
can't see the other 3 attempts at posting this.
Remember, plain text is your friend ;)