||FIG. 4. Whole-mount in situ hybridization with xHB9. Whole mount in situ hybridization was performed on Xenopus embryos at
different developmental stages. (A) Late gastrula (stage 13), lateral view, arrow depicts signal and points to the anterior-dorsal region of
the embryo; the blastopore is to the right; (B) late neurula (stage 20); (C) early tailbud (stage 23); (D) late tailbud (stage 26), arrows designate
retina and pituitary gland signal; dark staining in the gut cavity is background; (E) hatching stage (stage 33/34), arrow shows tailbud
staining; (F) swimming tadpole (stage 37/38), arrow designates signal in retina; (G) longitudinal section through spinal cord region of a
stage 35 embryo; (H) transverse section through the spinal cord region of a stage 35 embryo; (I) transverse section through the tailbud
region of a stage 35 embryo; arrow designates tailbud staining. Bars in A–F correspond to 0.5 mm; bars in G–I correspond to 0.1 mm.