Two P{lacW} insertions are present at the same site and in the same orientation in the 5' untranslated region, 37bp downstream from the start of the transcription unit.
Homozygous flies show a reduced attraction to alcohol in an olfactory assay compared to control flies. Mutants also show a reduced olfactory response to 1% acetic acid and 1/32% 3-pentanone compared to controls.
Excision of the insertions reverts the mutant olfactory phenotype.