Fig. 1

Phenotypes of pectoral fins in tbx5a-deficient embryos. Wild-type embryos with bilateral normal development of the pectoral fin (A,B). Unilateral hypoplasia (C), unilateral agenesis (D), and bilateral agenesis (E) of the pectoral fin in tbx5a morphants at 96 hpf. The rate of normal fin development was significantly reduced in tbx5a-deficient embryos at 48, 72, and 96 hpf (F). a, b: A significant difference was detected by one-way ANOVA with Duncan’s multiple range test. WT: Uninjected group, MIS: Control MO-injected group, MO: tbx5a morphant group. (G) Cross section of embryos with morphologic unilateral agenesis of the pectoral fin with Alcian blue staining showing well-organized glycosaminoglycans (GAGs) in the normal pectoral fin (blue arrow) with complete absence of chondrocytes and GAGs at the aplasia site (red arrow). (H) Cross section of the embryo with morphologic bilateral hypoplasia/agenesis of the pectoral fin showing the absence of chondrocytes and GAGs at the aplasia site (red arrow) with disorganized GAGs in the hypoplastic pectoral fin (red box). (I) Cross section of the embryo with morphologic unilateral hypoplasia of the pectoral fin showing disorganized GAGs in the hypoplastic pectoral fin (black box) and well-organized GAGs in the normal pectoral fin (blue arrow).