When such flies are also made heterozygous for a single copy loss of wingless , extensive loss of wing margin tissue is observed, suggesting a dominant synergistic interaction between wg and sno . Genetic combination of a weak allele of cut with a sno mutation shows extensive loss of wing margin tissue, suggesting a synergistic interaction between sno and cut . In addition to the wing margin defects, sno mutants also exhibit thickening of wing veins. A single copy of Hairless , is able to suppress the wing defects of heterozygous sno , suggesting that Hairless and sno exhibit related antagonistic activities downstream of the Notch pathway. Legs of mutant flies grown at nonpermissive temperatures show fused second and third tarsal segments as well as a less severe fusion of fourth and fifth tarsal segments.
Mutant flies have rough eyes.
Eye bristles, normally present at alternative corners of each facet, are often misplaced and sometimes duplicated. The extra cell is positioned between R3 and R4 where a mystery cell would have been in an earlier column. This suggests that in the mutant, a mystery cell fails to leave the precluster, giving rise to a 6-cell precluster. For example, split alleles of Notch affect the eye, while notchoid alleles affect the wing. In double mutant combinations with sno , the phenotypes in these respective tissues are enhanced.