Fig. 1: Phylogeny and revised nomenclature of placozoan iGluRs.
a Species aware phylogenetic tree of identified iGluR proteins sequences from select eukaryotes and metazoans. The letters D (red) and S (cyan) denote predicted duplication and speciation and events, respectively, predicted by the GeneRax software32. b Maximum likelihood phylogenetic tree of placozoan iGluRs reveals invariable AKDF orthologues and a diversity of epsilon receptors falling within three major clades (1 to 3 labeled in red font). The black numbers on the nodes of the tree indicate ultrafast bootstrap values for 1000 replicates. Top cell type expression based from single cell RNA-Seq data25, predicted ligand selectivity for glycine/D-serine vs. glutamate are indicated by symbols to the right of the tree according to the corresponding legends, and aligned amino acids sequences associated with ligand binding and ion permeation are indicated below the alignments. Horizontal solid blue and dashed black lines running behind the aligned residues are used to demark different clades of placozoan iGluRs according to our proposed nomenclature indicated on the right of the phylogenetic tree.
