A number of parameters were used to assess the effect of adult globin delivery to tadpoles. These included behavioural (average burst speed in tadpoles and maximum jump length in metamorphs), developmental (time to metamorphosis, weight and length at various developmental stages, protein profile of adult globin by PAGE) and genetic (mRNA levels for adult globin) measures. However, we were unable to detect any differences between treated and control animals following immunisation with purified globin or exposure to recombinant virus. This contrasts markedly with the effects of globin immunisation in R. catesbeiana reported previously by Maniatis et al. [18] , who speculated that some form of immune response was instrumental in the altered adult globin profile observed in injected tadpoles.