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Fig. 5. Ihh signalling from secondary chondrocytes. (A,D,G,) Alcian
Blue/Chlorantine Fast Red stained controls. (A-C) At e11, Ihh is
expressed by SCs (B), but, as shown on an adjacent section (C), ptc2
expression is at the limit of detection in the germinal region (white
arrowhead); however, it is expressed in the feather buds (FB; inset in C).
(D-F) At e12, Ihh is expressed by SCs (E), and ptc2 (F) is
expressed in the germinal region (arrowhead). (G-I) At e14, the relationship
between Ihh (H) and ptc2 (I) expression is maintained,
brackets indicate extent of the germinal region. Scale bars: 100 µm.