The time course for the appearance of adult globin mRNA and the disappearance of tadpole globin mRNA during normal cane toad metamorphosis were first assessed by real time PCR (Fig. 1a) . Tadpole globin mRNA was detected at all early stages until the level declined rapidly at the metamorphic climax (Stages 42-46) and was undetectable one month after metamorphosis. Conversely, adult globin mRNA was first detectable at stage 40 and at all following stages until the experiment was terminated.