Fig. 2. Somite segmentation is unnecessary for MiP and CaP specification. (A-E) Islet antibody + islet2 in situ hybridization at 18-21 hpf (A-C) and 24 hpf (D,E). Lateral views of the trunk of a fss;yot (A), Df^b380 (B) and Df^b567 (C) mutant and the tail of an aei mutant (D) and an aei wild-type sibling (E). Wild-type staining is shown in Fig. 1L. Islet antibody staining is nuclear and brown; islet2 staining is blue and cytoplasmic; ^*brown-only cells (MiPs). Comparison of double staining and single in situ hybridization (only shown for Df^b567; F,M) shows that MiPs and CaPs are specified normally in all of these mutants. (F,M) Lateral views of Df^b567 mutants. (F) islet1 in situ hybridization at 16-18 hpf. (M) islet2 in situ hybridization at 17-19 hpf. In both F and M, out of register PMNs on the other side of the embryo are clearly visible (+), although out of focus. This is never seen in wild types (see Fig. 1B,G). (G-L) znp1 antibody staining at 26-30 hpf. Lateral views of whole-mount fss;yot (G), Df^b380 (H), Df^b567 (J), and aei (K,L) mutants, and cross-section through the trunk of a Df^b380 mutant (I). Wild-type staining is shown in Fig. 1Q,W. (K) The posterior and (L) anterior of an aei mutant trunk. Ventral CaP axons (black circle) and dorsal MiP axons (white arrow) are visible in all cases. Scale bar: 50 µm in A-G,I-M; 25 µm in H.