Fig. 4

Expression of synaptotagmin gene ortholog in embryo and juvenile of the acoel S. roscoffensis. a ISH expression patterns on approximately 24 h post-fertilization embryos. Asterisk indicates the anterior pole of the embryo. b ISH expression pattern in juveniles from 12 to 24 h post-hatching. Arrowhead indicates the position of the statocyst and the anterior part of the juvenile. c FISH expression pattern (in green) combined with anti-SrStg antibody (in pink) on a 12–24 post-hatching juvenile. Embryo scale bar 60 μm; Juveniles scale bar 100 μm