Fig. 3

Phylogenetic analysis and characterization of opsins. a Phylogeny showing that representative bilaterian opsin members cluster into four supported subfamilies. Smp, S. mansoni and Sha, S. haematobium. Branch support values are indicated next to branching points. Maximum-likelihood bootstrap support values (significant support threshold value >60 %) are indicated as the first set of numbers at the nodes. Neighbor-joining bootstrap support values are indicated as the second set of numbers at the nodes, with bootstrap value expressed values above 60 % shown. Scale-bar indicates the relative amount of amino acid changes. b Partial amino acid alignment of members of the Gq-opsin subfamilies. Asterisks demarcate the fingerprint indicative of Gq-opsin families. An arrowhead demarcates the position of the lysine residue critical for Schiff base formation. c Schematic representation of S. mansoni opsin compared with the S. haematobium homologs. Circle shows region from panel b and asterisks demarcate presence of the Gq-opsin fingerprint