Fig. 3

Wnt expression in one-gill-slit amphioxus larvae. a Anterior expression domains of selected Wnt genes ordered as in Fig. 2: Wnt8, posterior cerebral vesicle (black arrowhead), preoral pit (pp), endostyle, and around the mouth; Wnt4, posterior cerebral vesicle (black arrowhead) and neural tube; Wnt5, cerebral vesicle (black arrowhead), club-shaped gland (cg), and weakly in anterior notochord; Wnt6, isolated spots in neural tube (black arrowhead); Wnt7, posterior cerebral vesicle (black arrowhead); Wnt16, neural tube, including the hindbrain (black arrowheads); Wnt10, posterior cerebral vesicle (black arrowhead); Wnt2, anterior notochord (black arrow), and isolated cells of the anterior endoderm; Wnt9, posterior cerebral vesicle (black arrowhead), pharyngeal endoderm around the preoral pit, endostyle, and the first gill slit primordium (black arrow); WntA, around the mouth and in the first forming gill slit (black arrow) and within the rostral coelom and muscle. Black asterisk indicates pigment spot in the forming frontal eye; white dotted line indicates mouth. b Posterior expression domains. Wnt1, posterior neural tube (white arrowheads) and neurenteric canal hinge (black arrowhead); Wnt11, tail fin (black arrowhead); Wnt5, tailbud region; Wnt6, neural tube (black arrow) and posterior wall of the neurenteric canal (black arrowhead); Wnt16, posterior wall of the neurenteric canal and posterior mesoderm of the last somites (black arrowhead); Wnt2, posterior notochord (black arrowhead); Wnt9, midgut endoderm (black arrowhead); WntA, mesothelial cells (black arrowhead). Older larvae have tail fins containing brown pigment. All views are lateral, with anterior to the left and posterior to the right