Phylogenetic analysis of 277 human G-protein-coupled receptors as a tool for the prediction of orphan receptor ligands

G-protein-coupled receptors (GPCRs) are the largest and most diverse family of transmembrane receptors. A pylogenetic analysis shows the overall relationship of 277 human GPCRs. An emphasis on receptors with no identified natural ligand may prove valuable for identification of the ligands of 'orphan' receptors.