Neighbor-joining phylogenetic trees for the Family A, Group V receptors. (A) Rooted tree for the opioid, somatostatin, galanin, and allatostatin receptors. (B) Unrooted tree for the gonadotropin releasing hormone (GnRH), vasopressin, and oxytocin receptors. The likely midpoint of the tree is indicated with an “X.” (C) Rooted tree for the glycoprotein hormone receptors and related leucine-rich repeat containing receptors (LGRs). Bootstrap scores, omitted branches, and Drosophila GPCRs are indicated as in Fig. 1. (ALGR) Anthopleura elegantissima (sea anemone) LGR; (FSHR) follicle-stimulating hormone receptor; (GALR) galanin receptor type 1; (GALS) galanin receptor type 2; (GALT) galanin receptor type 3; (GPR24 and GPR54) mammalian orphan GPCRs; (GRHR) GnRH receptor; (ITR) isotocin receptor; (LGR4–7) LGR types 4–7; (LSCPR and LSCPR2) Lymnaea stagnalis conopressin receptor types 1 and 2; (LSHR) lutropin-choriogonadotropic hormone receptor; (MTR) mesotocin receptor; (NLGR) C. elegans LGR; (ORPH4) Lymnaea stagnalis orphan GPCR; (OPRD) delta-type opioid receptor; (OPRK) kappa-type opioid receptor; (OPRM) mu-type opioid receptor; (OPRX) nociceptin/orphanin FQ receptor; (OXYR) oxytocin receptor; (SLGR)L. stagnalis GRL101; (SSR1–SSR5) somatostatin receptor types 1–5; (TSHR) thyrotropin receptor; (V1AR and V1BR) vasopressin V1A and V1B receptors; (V2R) vasopressin V2 receptor; (VTR) vasostocin receptor. The remaining non-Drosophila sequences are orphan GPCRs from C. elegans.
