In(1)sc^S1Lsc^8R and derivatives carrying this inversion carry two copies of the sc transcription unit, but neither copy is expressed normally, so flies have incompletely penetrant missing or duplicated macrochaetae phenotypes. In other words, the combination of the sc^S1 and sc⁸ alleles on the same chromosome produces mutant phenotypes.

Viable and fertile in both males and homozygous females; effective in suppressing crossing over with a normal-sequence X chromosome. Exists with many marker combinations, most of which were assembled by Muller.