Histology of claw development in
. Panels to the left (A,B,E,F,I,J) depict DAPI staining for nuclei in the developing claws in frontal section. Panels to the right (C,D,G,H,K,L) depict trichrome staining of developing claws in longitudinal section. Panels (A,C,E,G,K) and (L) are sections of clawed digits; panels (B,D,F,H) and (J) are sections of unclawed/reduced-clawed digits; panel (I) shows adjacent clawed (digit III, above) and unclawed (digit II, below) digits. (A,B) Early stage 35 (manual digits). (C,D) Late stage 35 (manual digits). Asterisk indicates the location of the fold in the epidermis dorsal to the claw. (E-J) Late stage 36 (pedal digits). In (E) and (H), the arrow indicates the location of the apex of the hinge between the developing claw and the overlying dorsal scale. (K,L) Keratinized claw (manual digit III) at early and late stage 37, respectively. (C,D) Asterisk indicates position of claw fold. (E-H) Arrow indicates base of hinge between the claw and the dorsal scale. Scale bar 100 μm for (A-H,J), 500 μm for (I) and 100 μm for (K,L).