De novo genome assembly of the Edwardsiid anthozoan Edwardsia elegans.

Cnidarians (sea anemones, corals, hydroids, and jellyfish) are a key outgroup for comparisons with bilateral animals to trace the evolution of genomic complexity and diversity within the animal kingdom, as they separated from most other animals 100 s of million years ago. Cnidarians have extensive diversity, yet the paucity of genomic resources limits our ability to compare genomic variation between cnidarian clades and species. Here, we report the genome for Edwardsia elegans, a sea anemone in the most specious genus of the family Edwardsiidae, a phylogenetically important family of sea anemones that contains the model anemone Nematostella vectensis. The E. elegans genome is 396 Mb in length and is predicted to encode approximately 49,000 proteins. We annotated a large conservation of macrosynteny between E. elegans and other Edwardsiidae anemones as well as conservation of both microRNAs and ultra-conserved noncoding elements previously reported in other cnidarians species. We also highlight microsyntenic variation of clustered developmental genes and ancient gene clusters that vary between species of sea anemones, despite previous research showing conservation between cnidarians and bilaterians. Overall, our analysis of the E. elegans genome highlights the importance of using multiple species to represent a taxonomic group for genomic comparisons, where genomic variation can be missed for large and diverse clades.