Fig. 2: Divergence times and conserved synteny blocks in the Cnidaria.

a, Separation of the major cnidarian groups occurred >500 Ma. Each group underwent an extended period of independent evolution. Species names are colour coded according to cnidarian classes: Anthozoa (green), Hydrozoa (blue), Cubozoa (orange) and Scyphozoa (red). Horizontal grey bars represent the 95% credibility intervals derived from posterior distributions. b, Aurelia–Nematostella synteny map. Scaffold groups that belong to ancestral Nematostella–human linkage groups (PALs) are marked with coloured boxes: PAL A (red), PAL B (green) and PAL C (blue). c, The most prominent linkage groups between Aurelia and Nematostella correspond to regions where the highest conservation also exists between Nematostella and human genomes. Coloured lines connect the locations of orthologous genes in the scaffolds of Aurelia and Nematostella. Scaffolds are depicted as black vertical lines. Scaffold number is shown at the bottom of each line. d, Aurelia–Morbakka synteny map, indicating that the genome of Morbakka has been strongly reshuffled. Fewer synteny blocks remain compared with the Nematostella–Aurelia pair despite the scaffolds of Morbakka being on average ~4× longer than those of Nematostella.