Fig. 4

(A) Nomarski pictures showing pectoral fins of wt and syu alleles in dorsal views. In the weak alleles, syu^tq252 and syu^tbq70, the pectoral fin phenotype is variable and frequently only the pectoral fin on one side of the embryo is reduced in size. In the strong allele, syu^tbx392/t4, the pectoral fins on both sides are reproducibly tiny and in the deletion allele syu^t4 finbuds are established (arrow) but fail to grow out. (B) Pectoral fins; dorsal views of shh whole-mount in situ hybridizations on syu alleles at 36 hpf. (C) Lateral views of shh whole-mount in situ hybridizations on syu alleles at 22 hpf. In the weak alleles, syu^tq252 and syu^tbq70, expression of shh is reduced, in embryos that carry syu^tbx392 over the shh deletion (syu^t4), it is barely detectable and no shh expression is seen in syu^t4 mutant embryos.