styΔ5/+ does not cause significant cardiac enlargement or reduced fractional shortening in adult hearts.
Eggs derived from egg chambers containing complete homozygous follicle cell clones have an expanded dorsal midline region, with the dorsal appendages being further apart than normal. In addition, most of the appendages are mildly shorter in length or thicker in width than normal, some have branched tips, and rarely, a small pseudo-appendage is seen at the base of one of the appendages.
Eggs derived from females with mosaic styΔ5 egg chambers occasionally have multiple, ectopic dorsal appendages. More commonly, the eggs have thinner dorsal appendages that are located more laterally than normal.
styΔ5 larva show extra terminal cells in their tracheal systems, when compared to wild-type larva.
styΔ5 homozygous clones in the dorsal air sac primordium are found at the tip of the primordium at a significantly lower frequency than wild-type clones.
Homozygotes have a variable number of outer photoreceptor neurons per ommatidium; some ommatidia have more and some have fewer than the normal number of outer photoreceptor neurons, and although the average number is 6.01 per ommatidium in the mutant (almost the same as wild type), the standard deviation is large (1.05).
When mutant somatic clones are made in the border cells no effect is seen.
Homozygous eggs are not recovered from females containing homozygous germ line clones, suggesting a requirement for sty function in the germline.
Escapers of lethality show a disorganized eye phenotype. Majority of ommatidia have extra R7 cells, generated by transformation of cone cells. Some of the extra photoreceptors resemble outer (R1-R6) photoreceptor neurons. Mystery cells assume R3/R4 fates. In heterozygous condition, 1-7% of ommatidia show an extra R7 cell or an occasional gain or loss of an outer photoreceptor cell. In embryos, 26% of hemisegments show an extra chordotonal organ in the lateral cluster. Midline glial cells are increased in number.
When clones are induced in the ovary, or specifically in the follicle cells, a range of phenotypes occurs, depending on the size of the clone. Eggs may be dorsalized, dorsal appendages may be misplaced or enlarged, and, rarely, dorsal appendages may be duplicated or split.
Pupal lethal when hemizygous. 30-120% more tracheal branches than normal bud from the dorsal, lateral trunk anterior, lateral trunk posterior, ganglionic and visceral branches. These additional branches arise from the stalks of the primary branches, close to the positions where secondary and terminal branches normally bud. The total number of tracheal cells is not increased in these embryos. In homozygous clones in which only the tracheal tip cell GB1 is sty-, there is always an ectopic branch in the neighbouring sty+ stalk cell, GB2. These ectopic branches usually turn away from the ventral nerve cord, and growth of the normal branch from the sty- GB1 cell may be slowed. In contrast, in clones in which a subset of stalk cells (GB2-7) are sty- and GB1 is sty+, the ganglionic branch generally appears normal, with no ectopic branches. In clones in which the tracheal tip cell DB1 is sty-, nearby sty+ cells form ectopic branches.