Fig. 1

Independent OLF gene expansions in ray-finned fishes. a Total number of OLF genes in 201 ray-finned fish species, coloured by gene family (Additional file 2: Table S1). Median value is indicated (M.). Right, number of OR, TAAR, V1R and V2R receptors found in different genomic clusters for those species with the higher number of genes within each of the taxonomic orders presenting more than 500 OLF genes (Additional file 2: Table S2). Loci containing less than five receptor genes are excluded for visualization purposes. b Number of receptor genes in each genomic cluster, normalized by species. Homologous gene clusters (cells) are displayed in columns. White cells represent the absence of homologous gene clusters. Dashed lines indicate clusters of traceable homologous origin physically separated by genomic rearrangements. Loci containing less than five receptor genes in all species are excluded from the plot. c Heatmaps showing intraspecific pairwise sequence identity (PSI) between individual OR receptors plotted following their genomic order in the European eel (A. anguilla) and zig-zag eel (M. armatus). Gene clusters are delimited by red squares. While higher sequence identity is generally restricted to receptors from the same clusters, the zig-zag eel presents a lineage-specific cluster containing OR genes very similar to the ones located in the larger locus. Loci containing less than five OR genes are excluded