Fig. 7. FGF8 and RA induce members of the other signaling pathways in animal caps. Embryos were microinjected with mRNA encoding FGF8 mRNA. Caps were cut from FGF8 or control embryos at or before stage 9 and allowed to develop until untreated sibling embryos reached stage 20 in the presence or absence of 10^–6 M all-trans RA. RNA was prepared from the caps and control embryos and QRT-PCR analysis performed with the indicated primer sets. Experiments were performed in triplicate and reproduced in independent experiments (Student's paired t-test). P<0.03 for all data sets.