Fig. 7. Differentiation of distal chondrocytes is accelerated in Col2a1-Ihh mice. Sections of E16.5 wild-type (A,C) and Col2a1-Ihh (B,D) limbs were hybridized with Fgfr1 (A,B) and Fgfr3 (C,D) riboprobes. (A1-D1) are higher magnifications of boxed regions in A-D, the dashed line in B,B1 demarcates the end of the radius, which is partially fused with the carpal navicular lunare in Col2a1-Ihh mice. The domain of Fgfr1 expression is reduced in Col2a1-Ihh mice (A,B, green arrow). The domain of Fgfr3 expression is broadened and shifted towards the end of the skeletal elements in Col2a1-Ihh mice (C,D, blue arrow in C1,D1). (E) The Fgfr1 expression domain (green arrow in A,B) is reduced in Col2a1-Ihh limbs (^*P=0.003, n=3) whereas the domain of Fgfr3 expression (blue arrow in C,D) is strongly expanded compared to that of wild-type limbs (^**P=0.007, n=3).