Origin of GPCRs Figure 1. Alignment showing shared and group specific motifs between Rhodopsin and cAMP like receptors in eukaryotes. We include consensus sequences obtained for each of the known 13 subgroups (colored red) of the large Rhodopsin family members from H. sapiens and a lone cAMP member from C. intestinalis to represent the Metazoan lineage. The alignment includes the identified cAMP like sequences from B. floridae (Brafl1_117719), L. gigantea (Lotgi1_158835), M. brevicollis (Mb_33227) a Choanoflagellata, consensus sequence obtained from 51 cAMP receptors from Fungi (Dicty_CAR_Fungi), and Alveolata (8) and Rhodopsin like sequences found only from 3 species, A. macrogynus (3) from Blastocladiomycota, B. dendrobatidis (BDEG_02994) and S. punctatus (8) which are member of the Chytridiomycota, an ancestral fungal lineage. The alignment also includes 10 cAMP receptor sequences from plants, obtained from Pfam database. The sequences are grouped based on family as cAMP and Rhodopsin like with respective to the major lineages across the eukaryotic tree to display the distinctive and shared motifs between them. The sequences which are marked with asterisk (red) received 7tm_1 (Rhodopsin like) as the best domain hit for HMM search against Pfam A families. We grouped those 8 sequences as cAMP receptors based on motifs and with strong support from phylogeny. The sequence (BDEG_02994, colored green) has only 5 TM domains, but was included as a lone representative for cAMP in Chytridiomycota. Major group specific motifs are indicated in PLoS ONE | www.plosone.org 3 January 2012 | Volume 7 | Issue 1 | e29817