A GENETIC SCREEN FOR MUTATIONS THAT DISRUPT AN AUDITORY RESPONSE IN DROSOPHILA-MELANOGASTER

Hearing is one of the last sensory modalities to be subjected to genet ic analysis in Drosophila melanogaster. We describe a behavioral assay for auditory function involving courtship among groups of males trigg ered by the pulse component of the courtship song, In a mutagenesis sc reen for mutations that disrupt the auditory response, we have recover ed 15 mutations that either reduce or abolish this response. Mutant au diograms indicate that seven mutants reduced the amplitude of the resp onse at all intensities. Another seven abolished the response altogeth er. The other mutant, 5L3, responded only at high sound intensities, i ndicating that the threshold was shifted in this mutant, Six mutants w ere characterized in greater detail. 5L3 had a general courtship defec t; courtship of females by 5L3 males also was affected strongly. 5P1 m ales courted females normally but had reduced success at copulation. 5 P1 and 5N18 showed a significant decrement in olfactory response, indi cating that the defects in these mutations are not specific to the aud itory pathway. Two other mutants, 5M8 and 5N30, produced amotile sperm although in 5N30 this phenotype was genetically separable from the au ditory phenotype. Finally, a new adult circling behavior phenotype, th e pirouette phenotype, associated with massive neurodegeneration in th e brain, was discovered in two mutants, 5G10 and 5N18. This study prov ides the basis for a genetic and molecular dissection of auditory mech anosensation and auditory behavior.