Fig. 4. Dorsal muscle specification and elongation are normal in gyc76C mutant embryos.

(A,B) Schematic diagrams of somatic muscles highlighting the external dorsal oblique (DO) muscles (A,B, red) and the internal dorsal acute (DA) muscles (A,B, yellow). In gyc76C²³⁸⁸ heterozygous and homozygous embryos (C,D), DO and DA muscles labeled with Kruppel (Kr) (C′,D′, white) are specified normally. In gyc76C²³⁸⁸ heterozygous (E) and homozygous (F) embryos, DO and DA muscles elongate to span the entire length of the segment (E,F, arrows). Embryos in C,D were stained for Kr in white and β3t in green, whereas embryos in E,F were stained for Tropomyosin. All embryos were stained for β-galactosidase (β-gal) to distinguish heterozygous from homozygous embryos (not shown). Embryos in C,D are at stage 12 and those in E,F at stage 14. Diagrams in A,B were adapted from Beckett and Baylies, 2003. Scale bar in B represents 5 µm.