Table 1 Average pairwise identities between odorant receptor families. Pairwise comparisons were performed between each member of a family with each member of the family to be compared. The average percent identity was then calculated for all comparisons between each pair of families. Similar results were obtained for consensus sequences of each family generated from Hidden Markov Models (HMMs) of each family. Zebrafish families are labeled A-H according to Figure 2a. The two major groups of mouse genes are denoted as "Class I" and "Class II." The maximum percent identity between families used to guide family classification of phylogenetic clades was 40% identity.