Fig. 2

Comparison of regional gene expression patterns in the dorsal mesoderm of amphioxus and vertebrates. a–d In situ hybridization of (a) mid- and (c) late-gastrula amphioxus embryos and (b) stage 10.5 and (d) 12.5 Xenopus embryos for dkk1/2/4, gsc, delta, bra, and wnt8. Bfgsc expression was detected in the anterior endoderm that forms the foregut. ga gastrula, st stage, ae anterior endoderm, s somite. e Fluorescence in situ hybridization of late gastrula amphioxus embryos stained with gsc/delta (Green). CellMask stained plasma membranes (red) and DAPI stained nuclei (blue). f Summary of dorsal mesoderm gene expression in amphioxus and vertebrates. Arrows indicate shifts of developmental stages from early- to late-gastrula stage. rm rostral mesoderm, hm head mesoderm, tm trunk mesoderm. Scale bars, 50 μm in amphioxus, 500 μm in Xenopus