New Insights into Ligand-Receptor Pairing and Coevolution of Relaxin Family Peptides and Their Receptors in Teleosts

Figure 2

Post 3R gene loss and gain in five teleost fish species. Following 3R, teleosts start with a gene set composed of 10 receptors and 6 ligands. Prior to divergence of zebrafish, rxfp3-3a is locally duplicated, generating tandem genes rxfp3-3a1 and rxfp3-3a2. Zebrafish retains most of the genes, except rxfp4, but gains an additional copy of the rxfp3-3 gene, rxfp3-3a3, through SSD. Other teleosts lose rxfp2-like and also the 3R-duplicate rxfp2b. SSD: small-scale (local) duplication. 3R: fish-specific WGD. Data from Yegorov and Good [2]. Phylogeny and classification of fish adapted from Kinoshita et al. [4].