Complete deletion from between the two P-element sequences of the sequences originating from the 1A region of the X chromosome that are present on the In(1)y2ps21cscws progenitor chromosome.
Mutants show complete reversion of the sc mutant phenotype compared to the In(1)y2ps21cscws progenitor. Pigmentation of the abdomen is not altered relative to the In(1)y2ps21cscws progenitor.