Six3 and Hh signaling do not regulate each other during early segmentation. (A,B) Expression of ptch2 in eight-somite stage control (A) and six3b;six7-deficient (B) embryos. (C-F) Expression of six3b (C,D) and six7 (E,F) in eight-somite stage wild-type embryos treated from 6 hpf with 10 μM cyclopamine (D,F) and embryos treated with 0.1% ethanol alone (C,E). Embryos are shown in lateral view with anterior towards the left. Insets show same embryo as dorsal view with anterior towards the left. Scale bars: 100 μm.