Fig. 9.

A simplified version of some of the key genes involved in pelvic fin/hindlimb development. It should be noted that some of these genes have not yet been investigated in pelvic fins. Both Hoxd9a and Hoxc10a have been shown to be involved in the positioning of the pelvic appendage in amniotes and teleosts. Wnt8c has the ability to induce ectopic hindlimbs in chick. The hindlimb identity genes Tbx4 and Pitx1 have both been shown to play roles in hindlimb specification and initiation. A positive feedback loop between Fgf10 in the mesoderm, Fgf8 in the apical ectoderm and Shh in the ZPA controls the outgrowth and patterning of the pelvic appendage.