Fig. 3

Organisation of HOX-related genes in corals and sea anemones. Relative positions and orientations of cluster H1 genes are largely conserved across taxa with the exception of Aiptasia. Arrows indicate the direction of transcription and colours distinguish between orthologous groups of genes identified by phylogenetic analysis. Genes that have been duplicated within a family are represented by multiple smaller arrows. The nomenclature used here for the H1 genes is based on Chourrout et al. [35] and Baumgarten et al. [20]; note that Mnx1 is also known as hlxB9. Unconnected arrows represent different scaffolds (two from Nematostella and two from Aiptasia); dotted lines indicate genes that were assembled on a different scaffold from other H1 genes, but can be putatively placed in the cluster by comparing gene arrangement with other species; arrows without outline indicate a manually corrected gene model; vertical wavy lines represent a long genomic distance with 10–20 genes between. Gene order and orientation in ParaHox cluster H2 are highly conserved in corals, whilst local gene rearrangement is observed in both sea anemones. Black box and circle represent the POMP and CD027 genes, respectively