Figure 1

The figure summarizes our findings in amphioxus in comparison with human GPCRs. The shape of the tree and the division are adopted from [4] and the black dots represent core nodes. The families are GLU, Glutamate; Rhod, Rhodopsin; ADH, Adhesion; FZD/TAS2, Frizzled/Taste2; SEC, Secretin; OA, Ocular albinism receptors; VR, Vomeronasal receptors. The Rhodopsin family is further split into α-, β- γ- and δ-groups. The subgroups in α are AMIN, serotonin/dopamine/adrenergic/trace amine receptors; MEC, melanocortin/Lysophospholipid (EDG)/adenosin/cannabinoid receptors; MTN, Melanotonin receptors; OPN, opsin-like receptors; PTG, prostaglandin receptors. In γ: CHEM, Chemokine-like receptors; MCH, Melanocyte concentrating hormone receptors; SOG, somatostatin/opioid/galanin receptors. In δ: LGR, glycoprotein binding receptors; MRG, MAS-related receptors; OLF, olfactory receptors; PUR, purine-like receptors. Orange leafs only hold amphioxus transcripts, purple only human and green leaves represent branches that hold genes from both species. The annotation at the end of each leaf is the number of GPCRs in each branch. The number without parenthesis is for amphioxus and that one within parenthesis is the number of human GPCRs according to [13].