Fig. 1

Lateral views of living noi and ace mutant embryos. (A) Wild-type embryo at 36 hours of development. (B) Sibling of the embryo in A that is homozygous mutant for a strong allele of noi (noi^th44). Absence of the tectum, cerebellum and MHB is indicated by an asterisk. (C) Embryo homozygous mutant for a weak allele of noi (noi^ty31a). A partially formed tectum, but no cerebellum or MHB, is observed. (D) Embryo homozygous mutant for acerebellar (ace^ti282a). An enlarged tectum is present, but no cerebellum or MHB are seen (see also Fig. 7). (E) Pronephric duct (pn) in a wild type and (F) homozygous mutant embryo for noi^th44. In the mutant embryos, no pronephric duct is found; the arrow points to the few cells in the mutant that may represent partially developed pronephric duct cells; consistent with the presence of a normal duct during earlier stages of development. (G) Blood streaming through the common cardinal vein over the yolk in a 36 h wild-type embryo (bracketed by arrows). (H) Blood cells accumulate in a dent on the ventral yolk sac in a homozygous mutant embryo for noi^th44. No such accumulation is seen in wild-type embryos. Embryos in A and B and E-F were placed in PTU at about 26 h to suppress formation of melanin. cb, cerebellum; ey, eye; tec, tectum; ov, otic vesicle; pn, pronephric duct. Scale bar, 150 µm (A-D), 60 µm (E-H).