Fig. 5. Functional “pseudogene” alleles of other receptors in other species.

a, Gene structure of D. melanogaster Ir75b indicating the position of the PTC in the RAL707 strain (an identical sequence is found in all other strains containing a PTC at this position; Methods). The region encoding the epitope recognised by anti-IR75b antibodies is indicated with a red bar.

b, Immunofluorescence with anti-IR75b antibodies on antennae of reference D. melanogaster (Methods) and RAL707 flies. Scale bar = 10 µm.

c, Quantification of odour-evoked responses in ac3 sensilla to propionic acid and butyric acid in control (reference D. melanogaster) and RAL707 flies. Boxplots indicate the median and first and third quartile of the data; each dot corresponds to one recording.

d, Gene structure of D. melanogaster Ir31a indicating the position of the PTC in the RAL441 strain.

e, Quantification of odour-evoked responses to 2-oxopentanoic acid in ac1 sensilla of control (reference D. melanogaster) and RAL441 flies.

f, Gene structure of D. melanogaster Or35a indicating the position of the PTC in the T09 (and T29) strain.

g, Quantification of odour-evoked responses to octanol in ac3 sensilla of control (reference D. melanogaster) and T09 flies.