Fig. 7

Fig. 7

Figure 7. Intermediate radials share a developmental identity with the limb zeugopod

Outlines of skeletons of wild-type and reph/+ mutant zebrafish pectoral fins and tetrapod limb. Both fins and limbs exhibit regional dependence on Hox cognate groups to properly form bones. Distal regions are dependent on Hox13 genes for their formation (blue background shading). Dermal fin rays (blue) are severely reduced in the absence of Hoxa13 paralogs, while the limb autopod does not form in the absence of Hoxa13 and Hoxd13. "Intermediate" regions are dependent on Hox11 genes (red background shading). The limb zeugopod fails to form long bones with loss of Hoxa11 and Hoxd11. Similarly, in reph/+ mutants, intermediate radials (orange) are not formed when Hoxa11 paralogs are lost. An intermediate regional dependence is not present in wild-type fins.