Fig. 1. Expression of notochord and endoderm markers following inhibition of ALK4/5/7 with SB431542. Embryo treatment is indicated at the top of the panels and the marker analysed is indicated at the left of the panels. Ci-Bra was analysed at the 64-cell stage, Ci-Titf at the early gastrula stage and Ci-Noto1 and Ci-Gataa at the early tailbud stage. For the top panel, the average number of cells expressing Ci-Bra is indicated; n=number of embryos analysed. For the rest of the panels, the numbers indicate the number of embryos expressing a given gene/total number of embryos analysed.