Fig. 2

Appa and Appb can replace each other and thus are redundant in early zebrafish development. A–D

Embryos were injected with sub-effective doses of appa and/or appb morpholino (MO). These doses produced no phenotype in the fish compared to control MO (A–C, see also Figure 1). D. When sub-effective doses of appa and appb MO were combined and injected, a strong phenotype emerged consisting of morphological malformations and death of tissues within the CNS (*). E. Quantifying this effect, the co-injection of sub-effective doses of both MOs produced a significant decrease in the number of normal fish (green bars) and a significant increase in number of fish displaying CNS cell death (mild in light orange bars; severe in dark orange bars). ** = P<0.01. F. Fish injected with appa MO can be rescued by co-injection with appa mRNA * = P<0.05. A similar result was attained for appb MO and its cognate mRNA (Fig. S2). G, H. Fish were injected with an effective dose of one MO along with cognate mRNA from the other paralog to see if rescue of the phenotype occurred. appb mRNA was able to effectively alleviate the phenotype caused by injection of the appa MO (G) and vice versa (H). ** = P<0.01.