Fig. 9. Increased apoptosis and altered gene expression in FGFR1-deficient limbs. (A-D) TUNEL assay on E11.5 wild type (A,C) and mutant (B,D) limbs. C and D are cross sections of hindlimbs of wild-type (C) and Fgfr1^Co/Co;AP-2Cre (D) mice. Note that the mutant limb shown in D is wider because of an increased length of the DV axis, which can only been seen in the cross sections. All other images are hindlimbs of wild type and Fgfr1^Co/Co;Hoxb6-Cre mice. (E-H) Whole-mount in situ hybridization of E10.5 (G,H, arrowheads indicate areas of Dkk1 expression), and E11.5 (E,F) limbs. Genotypes and probes are as indicated.