FIG. 1.—

Phylogenetic analysis of Nematostella vectensis and Strongylocentrotus purpuratus OR-like genes, cephalochordate, and vertebrate ORs, and a diversity rhodopsin-like GPCRs that includes the TAARs and the FPRs. The unrooted NJ tree is based on approximately 200 amino acid positions and Poisson-corrected distances. The tree was constructed using the pairwise deletion option, and support for nodes was estimated using 1,000 bootstrap replicates. The bootstrap values for major clades are shown and the scale bar below indicates distance. Non-OR rhodopsin-like GPCRs were included based on the α, β, γ, and δ subgroup classification (Fredriksson et al. 2003). A list of these genes is included in supplementary table S2 (Supplementary Material online). Type I and II vertebrate OR designations are based on the classification in Niimura and Nei (2005). Motif-containing sequences are marked with “▪” and non-OR rhodopsin-like GPCRs from cnidarians are marked with “▴.”