Phylogenetic analysis of the Rhodopsin family. The figure shows a phylogenetic tree of Rhodopsin family receptors. Rhodopsins which display ambiguous relationships were analysed in separate (see Figure 2). Species-specific receptors have names in bold style. The ligand types of the receptors are indicated with the following colours; red: orphan, blue: peptide, lilac: amine, green: lipid-like, brown: purine, turquoise: opsin and black: other. The first pie chart above the trees shows the proportions of human-rat one-to-one orthologues (O), human specific (H) and rat specific (R) members. The second pie chart displays the proportions of rat-mouse one-to-one orthologues (O), rat specific (R) and mouse specific (M) members. This phylogenetic tree is a consensus tree of 2 consensus trees derived from 100 maximum parsimony and neighbour joining analyses, respectively, and calculated using the UNIX version of the Phylip 3.6 package .