Figure 1.

(a) Summary of limb and long bone development. Limb development proceeds through several stages: limb bud outgrowth and patterning, when the limb bud is only filled with undifferentiated mesenchyme; morphogenesis, where the cartilaginous anlagen of the limb bones form; and growth, mediated from epiphyseal growth zones. FLB, forelimb bub; HLB, hindlimb bud; and GZ, growth zone. (b) Limb development for Anolis sagrei. Asterisks denote visible condensations in the digital plate of stage 7 embryos. The earliest samples in our study were collected during stage 9, the earliest time when cartilage stains with Alcian blue.