Fig. 7

ptc expression in con, syu, and yot. (A–F) Fin bud expression of ptc1 (A–C) and ptc2 (D–F) at 32 hpf. In all cases the fin buds are indicated with black arrows. Both ptc1 and ptc2 are expressed in wild-type fin buds but the ptc2 domain is both broader and weaker than that of ptc1 (A and D). In contrast neither gene is expressed in the fin buds of syu homozygotes (B and E) and expression of both ptc1 and ptc2 is reduced in the fin buds of con homozygotes (C and F) though ptc1 is affected more than ptc2. (G–J) Lateral views of ptc2 expression with anterior to the left. The rectangular brackets in G and I indicate the equivalent regions of embryos shown in close-up in H and J. At 24 hpf ptc2 expression is only slightly affected, if at all, by any of the “U” class of mutations. In yot homozygotes ptc2 expression is very slightly weaker than in wild-type embryos (I) but less so than in con or syu homozygotes; the one exception to this is in the anterior somites, where expression of ptc2 is eliminated (J).