Fig. 5. Morpholino co-injections reveal evidence of interactions between san, vtn and heg. Injection of low doses (10 and 15 µmol/l) of each morpholino alone is unable to produce large number of embryos with the characteristic enlarged heart and thin-walled myocardium. However, by injection of combinations of any two of the san, vtn and heg morpholinos, a dramatic increase in the level of phenocopy is observed (indicated by the increase in the yellow bars) with a concomitant decrease in the level of wild-type embryos (blue bars). A number of embryos (indicated by the red bars) display a phenotype intermediate between wild type and mutant, characterized by a less dramatic dilation of the heart and some with weak circulation. heg, heg exon 11 donor morpholino injected; san, san exon 1 donor morpholino injected; vtn, vtn exon 2 morpholino injected.