Phylogenetic tree of the fish Ora family. (A) Twenty-eight fish Ora (red), 15 frog Ora (green) with some mammalian V1R (light blue) representatives and T2R (orange) as the closest relatives. (B) Twenty-eight fish ora genes. Trees were constructed using the NJ method. Bootstrap support (total 1000 replications) is indicated at the major nodes. Scale bar indicates the number of amino acid substitutions per site. *, see Pfister and Rodriguez 2005; #, see Shi and Zhang 2007. Ora, olfactory receptors of class A; T2R, putative taste receptors of type 2 (Ishimaru et al. 2005); V1R, vomeronasal type 1 receptors (Grus et al. 2005). The V1R receptors are a subset of V1Rs from all mammalian organisms annotated in the NCBI database (mouse, rat, human) and described in publications (opossum, cow, dog; Grus et al. 2005). The phylogenetic position of the full mammalian V1R set of annotated and published genes is identical (cf. Supplemental Fig. 1).
