Bardet-Biedl syndrome genes are required for butanone enhancement in AWC^ON neurons, whereas other cilium structure genes are not required. A, Rescue of the olrn-2 butanone enhancement phenotype with the wild-type olrn-2 cDNA driven by str-2 (AWC^ON) and gcy-10 (AWB and AWC) promoters. Results of three independent lines of animals carrying extrachromosomal array are shown for each promoter. The selection assay was used to detect the rescue sensitively. Four to six plates were used for all data. *p < 0.005, **p < 0.05, comparing olrn-2 animals with each line of olrn-2 animals carrying transgenes for butanone enhancement. B, Mutants in Bardet-Biedl syndrome genes exhibited defects in butanone enhancement. olrn-2(ut306) is allelic to bbs-8(nx77), and osm-12 gene encodes the C. elegans BBS-7. Four to 15 plates were used for all data. C, Mutants in other cilium structure genes did not exhibit defects in butanone enhancement. gpa-3(gf) is a strain with a chromosomal insertion of the gain-of-function (Q205L) mutant gpa-3 transgenes. Four to 15 plates were used for all data. The error bars indicate SEM.