Figure 3. A Revised Phylogeny and Nomenclature of the Vertebrate Melanopsin Family.

A maximum parsimony phylogenetic tree (derived from amino acid sequences 310 sites, 151 informative, rooted with Amphioxus Opn4) showing the relationship between the novel nonmammalian Opn4m melanopsins and previously published Opn4x melanopsin sequences. Branch confidence levels (% based on 500 bootstrap replicates) reveal an evolutionarily ancient split into the Opn4m and Opn4x branches. The teleost melanopsin nomenclature previously suggested by Drivenes et al. [ 17] is shown in parenthesis; see text for more details.