Phylogenetic classification of ORs. Color coding by family as in Figure1. (a) Protein identity score (PID) of each detected OR to its most similar OR and non-OR G-protein coupled receptor (GPCR). Spheres represent olfactory receptors; small spheres denote OR pseudogenes. Note the very different scales on both axes: The dotted line corresponds to x = y. (b) Relative sizes of the 17 OR families observed, and the unclassified ORs. (c) Correlation between the number of subfamilies and number of ORs in each family, averaging two ORs per subfamily, except for families 2, 4, and 7. (d) Phylogenetic tree of family consensus sequences. These were derived by using a majority rule at each position in a family-specific multiple alignment. The phylogenetic tree was derived by using the neighbor-joining algorithm in CLUSTALW with 1000 rounds of bootstrap. The percentage bootstrap strength is indicated at each node. The horizontal bar indicates 10% divergence along each branch.
