Gene expression and digit homology in the chicken embryo wing.

@article{Welten2005GeneEA,
  title={Gene expression and digit homology in the chicken embryo wing.},
  author={Monique C. M. Welten and F. J. Verbeek and Annemarie H. Meijer and Michael Richardson},
  journal={Evolution & development},
  year={2005},
  volume={7 1},
  pages={18-28}
}
The bird wing is of special interest to students of homology and avian evolution. Fossil and developmental data give conflicting indications of digit homology if a pentadactyl "archetype" is assumed. Morphological signs of a vestigial digit I are seen in bird embryos, but no digit-like structure develops in wild-type embryos. To examine the developmental mechanisms of digit loss, we studied the expression of the high-mobility group box containing Sox9 gene, and bone morphogenetic protein… CONTINUE READING