Fig. 8. Absence of Gdf5 expression in the distal phalangeal interzone of Ror2^{W749FLAG/W749FLAG} mutants. Gdf5 expression was analyzed by in situ hybridization in limbs from wild-type (WT, A,C,E) and Ror2^{W749FLAG/W749FLAG} (B,D,F) embryos. (A,B) Whole-mount in situ hybridization of forelimbs from E12.5 embryos, showing identical patterns of Gdf5 expression in the mutant. (C,D) Sections of E13.5 forelimbs, revealing reduced expression of Gdf5 in the proximal phalangeal interzone of Ror2^{W749FLAG/W749FLAG} digits (D, 1/2). (E,F) Sections from E15.5 digits, showing normal Gdf5 expression levels in the proximal phalangeal interzone of the Ror2^{W749FLAG/W749FLAG} digit (F, 1/2), but absence of signal in the presumptive distal interzone (2/3). MC, metacarpal; P1, phalanx 1; P2, phalanx 2.