Fig. 7. Expression of Ci-ETR-1 and Ci-otx in vegetal cells of embryos placed in MEK inhibitor at various time points. Embryos were placed in cytochalasin B to arrest cell cleavage at the 64-cell stage. (A) Graph showing the percentage of embryos with expression of Ci-otx in A7.8 blastomeres in embryos placed in inhibitor at the time points shown along the x-axis. (B) Graph showing the percentage of expression in notochord precursors in embryos placed in inhibitor at the developmental time points shown along the x-axis. At the late 32-cell stage, one experiment showed 3% notochord expression, the other 99% expression. This is most likely to be due to slight differences in timing between the experiments.