Meeting Abstract
77-2 Sunday, Jan. 6 08:15 – 08:30 The complete genome sequence of Beroe ovata, a tentacle-less, ctenophore-chomping ctenophore DEBIASSE, MB*; BABONIS, LS; KOREN, S; SCHNITZLER, CE; MARTINDALE, MQ; RYAN, JF; Whitney Lab for Marine Bioscience; Whitney Lab for Marine Bioscience; National Human Genome Research Institute; Whitney Lab for Marine Bioscience; Whitney Lab for Marine Bioscience; Whitney Lab for Marine Bioscience melissa.debiasse@gmail.com http://melissadebiasse.weebly.com/
Ctenophores occupy an important place in the animal tree of life with respect to phylogeny and ecology, and characterizing ctenophore genome structure improves our understanding of animal diversity. Here we present the genome of the lobate ctenophore Beroe ovata. Given the divergent feeding ecology and morphology of Beroe compared to the species whose genomes were sequenced previously (Mnemiopsis leidyi and Pleurobrachia bachei), the B. ovata genome fills an important gap in our knowledge of ctenophore diversity. We assembled the B. ovata genome from Pacific Bioscience sequencing reads using Canu and a novel post-processing method that retains unique genes while reducing the number of erroneously incorporated haplotigs. Our B. ovata genome assembly is ~156 MB with an N50 of 187,314 and 16, 548 predicted genes. Assessments of assembly completeness were high with 91% and 96% of complete and complete+partial BUSCO core genes represented, respectively. We identified four Wnt pathway genes (WntA, WntX, Wnt6, Wnt9) in B. ovata that are expressed in tentacle bulbs in M. leidyi. This result is surprising given that B. ovata lacks tentacles and the regeneration ability associated with stem cells in tentacle bulbs. Beroe ovata has three opsin genes, but two lack the conserved lysine required for chromophore binding, meaning only one opsin is functional. The B. ovata genome has 48 photoprotein genes clustered on 8 different genomic scaffolds, 5x more than found in M. leidyi, suggesting a large-scale duplication in B. ovata photoprotein genes; these findings suggest the clustering of photoprotein genes in both M. leidyi and B. ovota is important for functional bioluminescence in ctenophores.
