Fig. 3. Localization of Xror2 transcripts visualized by whole-mount in situ hybridization. (A) Vegetal view of the gastrula (dorsal is upwards). (B) Hemisectioned early gastrula (animal is upwards; dorsal towards the right). Embryos were bisected sagittally before whole-mount in situ hybridization. (C) Comparison of expression domains between Xror2 (left panel) and Xlim-1 (right panel) at the gastrula stage. Embryos were bisected into left and right halves and subjected to in situ hybridization for Xlim-1 and Xror2, respectively. Dorsal is towards the right (Xror2) or the left (Xlim-1). (D) Late gastrula bisected sagittally (animal is upwards; dorsal towards the right). (E) Dorsal view of late gastrula (anterior is upwards). (F) Transverse section of stained embryos. Xror2 transcripts are detected in the notochord and neuroectoderm. (G,H) Dorsal view of mid-neurula embryos cleared with benzyl benzoate/benzyl alcohol. Xror2 transcripts were detected in the notochord and neuroectoderm with a clear anterior limit in the neuroectoderm. (I) Double whole-mount in situ analysis of Xror2 (magenta) and en2 (turquoise). Arrowheads, en2 expression. (J) Transverse section of neurula embryos. (K) Lateral view of tailbud-stage embryos. Numbers 1, 2, 3 and 4 indicate Xror2 expression in mandibular crest, hyoid crest, anterior branchial crest and posterior branchial crest segments, respectively. st., developmental stages.