Inversion, that was generated by recombination between the P{}y+sb insertion present in y+ls2.P and P-element insertions ("P3" and "P4") present in the ac-sc complex (these are two 1.2kb elements present in inverted orientation separated by 194bp of sequence from the ac-sc complex in the progenitor y+ls2.P allele). At one boundary of the In(1)y2ps21sces inversion, the P{}y+sb element has become linked to the ac-sc sequences. At the other boundary, the regulatory portion of the y gene is interrupted at -69; the P{}2ps21-P3 and P{}2ps21-P4 insertions from the ac-sc region are located between the y coding and the ac-sc sequences in tail-to-tail orientation.
Mutants have a strong sc mutant phenotype; most types of bristle are missing. Pigmentation of the abdomen is reduced compared to wild type, while pigmentation of the bristles is nearly normal.
