Males carrying P{hsw^a} and a source of transposase (P\T) have mosaic eyes, due to excision and repair in mitotic cells in the developing eye. Repair events are also occurring in developing mitotic germ line cells in these males, which can be detected by crossing the males to females homozygous for P{hsw^a}. The female progeny have 3 classes of eye colour; 92% have apricot-coloured eyes (these are probably derived from cells in which P{hsw^a} did not excise, but some may have resulted from excision followed by repair to restore the complete P{hsw^a} element). Almost 4% have flat red eyes (more than 90% of the red eyed flies have a single LTR remaining at the copia insertion site in the transgene). About 4% have yellow eyes, corresponding to aberrant repair events that result in the loss of w activity.

Flies carrying Δ2-3 have mosaic eyes showing both w^- patches and wild type patches, due to excision and internal deletion of the w sequences in the P element, respectively. The Hsp70 promoter, without induction, is comparable in strength to the white promoter in the relevant cells of the eye. Of 243 Δ2-3 induced derivatives of w^a.hs with increased eye pigmentation, 205 carried deletions within the copia and 201 of these were precise deletions between the directly repeated copia LTRs.