Fig. 2. Specificity of PG1 morpholinos. Two morpholinos for each Hox PG1 gene were injected into the left-hand side of the embryo and Krox20 (r3 and r5) and Engrailed-2 (midbrain/hindbrain boundary: ^* in A-I) expression analysed. The hindbrain region of early tailbud stage embryos (anterior to the top) is shown for non injected controls (NIC; A,D,G), Hoxa1 1st (B: 80%, n=15) and 2nd (C: 70%, n=10) morpholinos, Hoxb1 1st (E: 85%, n=13) and 2nd (F: 70%, n=20) morpholinos and Hoxd1 1st (H: 90%, n=11) and 2nd (I: 80%, n=15) morpholinos. Overexpression of Hoxd1 morpholino insensitive RNA (J) and rescue of Hoxd1 1st and 2nd morpholinos with Hoxd1 RNA is also shown (K,L). Dotted line indicates the midline.