Fig. 1.

Ir-Gal4 expression patterns and IR phylogeny. Summary of the expression (indicated by dark blue shading) of Gal4 drivers for the entire D. melanogaster IR repertoire in peripheral chemosensory organs in third instar larvae and adult flies (see also Figs 2 and 3). Some lines, in particular antennal-expressed drivers, were previously described^{15,20–22,25,28,39,41,74,75}. Light blue shading indicates additional expression reported for independently-generated Ir-Gal4 drivers^26,27. We did not distinguish expression in the dorsal pharyngeal organ and dorsal pharyngeal sense organ. The tree on the left shows a cladogram representing the phylogenetic relationships between D. melanogaster IRs. Protein sequences were aligned with MUSCLE, and the tree was made with RaxML under the WAG model of substitution, with 1000 bootstrap replicates. The columns on the right highlight drivers exhibiting common or stage-specific expression in larvae and adults