Fig. 3-S2

(A–B) The sox1a^u5039 allele shows incomplete penetrance with ~65% (n = 117/181) of homozygous mutants having a double-right dHb as confirmed by nrp1a mRNA in situ hybridisation at 4 dpf. lHb– left habenula, rHb – right habenula. (C–D,F) sox1a^ups8 allele exhibits complete penetrance with all homozygous mutants having a double-right dHb, as confirmed by nrp1a mRNA in situ hybridisation at 4 dpf in Tg(foxD3:GFP);(flh:eGFP) background with GFP expressed in the pineal complex (C and Figure 3). sox1a^+/ups8 heterozygotes (n = 45) (D) have a phenotype identical to wild-type siblings (F). (E) The two mutant sox1a alleles do not complement each other – all trans-heterozygote larvae are double-right for nrp1a mRNA expression (n = 45/45). Similar to sox1a^ups8, trans-heterozygotes of the two mutant alleles exhibit stalled outgrowth of parapineal axons (white arrows in C and E).