During development of the bristle lineage, Vang protein is localised in an anterior crescent in dividing sensillum precursor cells and promotes the anterior localization raps protein.

Vang acts together with fz and stan to mediate apicolateral recruitment of planar polarity proteins including dsh and pk. Vang has a role during planar polarity patterning.

Vang requires pk and stan function to regulate tissue polarity in the eye.

Genetic analysis is not consistent with fz-like class of genes fz, pk, Vang, stan and dsh acting simply as positive or negative regulators of in and fy.

Mutations in fz-like class of genes fz, pk, Vang, stan and dsh act as strong enhancers of weak in or fy phenotypes. fz and Vang show complementary domineering nonautonomy in the wing and abdomen.

The Vang gene product is essential for fz signalling. The Vang gene does not fall into the usual fz-like or in-like classification, defining a new type of tissue polarity gene. The Vang gene product acts cell nonautonomously.

Flies homozygous for Vang alleles show a tissue polarity bristle phenotype on the wing, thorax, legs and abdomen. On the abdomen, bristles point almost orthogonally to the midline instead of posteriorly. Tarsal joints are often duplicated. Flies have rough eyes. Phenotypic data suggest that genetics of Vang and its interactions with pk are complex. Several, but not all, Vang alleles act as enhancers of the pk haploinsufficient tissue polarity phenotype, and the pk^TBJ21 antimorphic phenotype. Mutations in pk can also act as suppressors of Vang dominant phenotypes.

Vang is required to establish polarity in the eye, legs and bristles.

Vang is involved in setting up polarity in the eye, legs and bristles. Mosaic analysis indicates Vang is required in all photoreceptors within an ommatidium to establish normal polarity of the ommatidium.

The definition of strabismus is: a disorder in vision due to a deviation from normal orientation of one or both eyes (the medical term for cross-eyed).