miR-196 duplex injection inhibits expression of zebrafish fin development genes. (A) Model of the pectoral fin developmental pathway (after (Mercader, 2007)). In situ hybridization for lbx1b (B, C), fgf10a (D, E), fgf24 (F, G), tbx5a (H, I), prdm1a (J, K), hoxc6a (L, M), on controls (B, D, F, H, J, L) and miR-196 over-expression (oe) animals (C, E, G, I, K, M) at ages indicated in the lower right of each panel. Arrowheads show the presumptive pectoral fin region in miR-196 duplex-injected animals. Results showed that miR-196 acts at or before the earliest stages of fin bud initiation. Abbreviations: cns, central neural system; ff, fin field; fm, pectoral fin muscle; im, intermediate mesoderm; ll, lateral line primordium; no, notochord; nt, neural tube; ov, otic vesicle; pa, pharyngeal arch; pf, pectoral fin bud; ro5, rhombomere 5.