The average number of crystal cells per embryo is significantly reduced in homozygous stage 13-14 embryos compared to wild type.
Homozygous embryos fail to undergo dorsal closure and show severe defects in the development of the peripheral nervous system (PNS); fewer neurons are present, especially in the dorsal and lateral PNS clusters (the ventral clusters are less affected). shnk04412/shn1 embryos show a reduction in the number of dorsal and lateral neurons of the peripheral nervous system.
Homozygous somatic clones induced during mid to late third larval instar stage are recovered at a significantly higher frequency than those induced earlier. Although homozygous mutant somatic clones induced after 90h after egg laying can be recovered throughout the anterior wing margin, they are observed at a much higher frequency in the region containing the triple row bristles compared to the double row bristle domain. Clones recovered in the triple row bristle domain tend to be larger than clones in the double row domain.
The Malpighian tubules of homozygous embryos elongate properly to the two cell circumference, although they are located abnormally in the embryo, coiling around their point of origin from the hindgut.
Homozygous embryos show bunching of epidermal segments at the end of dorsal closure.
Clones induced in the developing eye that span the morphogenetic furrow have condensed chromosomes indicative of early stages in mitosis at the interface between the CycB-expressing and non-expressing cells. Clones at the anterior edge of the furrow show mislocalized nuclei, they fail to reach the apical surface where mitosis normally takes place. Nuclei are also misplaced when the clone is within the furrow and posterior to it. Cell fate specification is not, however, affected.
Strong allele. Wing clones induced in mid-to-late third instar larvae are small due to their late induction time but cause visible mutant phenotypes: gaps, splits, vein indentations and additional vein material abutting normal veins. Wing veins are lost when the clone lies on the dominant, protruding, side of the vein. Cells at the edge on the clone are sometimes able to form vein material, reminiscent of the phenotypes of the "loss of vein" class of genes.
Dorsal closure fails, dorsal epidermis is significantly reduced. Denticles on the lateral region are abnormally oriented and disrupted.
Homozygous embryos show abnormal gut morphology and gut constrictions do not form. Cell fates are altered in the lateral position of the embryos, wing and haltere primordia do not express sna as they would in wild type.
Nondefective in gonad assembly.
embryonic lethal. Embryos lack dorsal hypoderm. Internal organs appear normal and extruded through the open dorsal side of the embryo. Ventral hypoderm contracted.