Meeting Abstract

P2-84   -   Gene novelty in understudied groups: using the chromosome-level genome of the nudibranch gastropod Berghia stephanieae as a case study Goodheart, JA*; Bigasin, A; Lyons, DC; University of California, San Diego; University of California, San Diego; University of California, San Diego jgoodheart@ucsd.edu https://jessicagoodheart.weebly.com/

Novel (or de novo) genes are considered a valuable way for new phenotypes to emerge during evolution. In Mollusca, a speciose and functionally diverse metazoan phylum, novel genes are thought to be recruited for processes such as biomineralization and some unusual molluscan features, such as the radula. But what does novelty mean in these contexts? Due to the lack of functionally well annotated genomic resources for many molluscs, researchers are often unable to identify homologs to their dataset using common databases, which leads to overestimates of novel genes. Gastropods, the most diverse class of molluscs, are particularly underrepresented when it comes to high quality genomic data. Here we present the genome for the nudibranch gastropod Berghia stephanieae, an emerging model species. This species has the unusual ability to sequester cnidarian nematocysts, which likely uses both evolutionarily novel and co-opted genes. Post filtration with purgedups and blobtoolkit, the B. stephanieae genome is in 18 scaffolds ( ~1.1 Gb) with an N50 of 86 Mb (6 scaffolds) and N90 of 44 Mb (15 scaffolds). We found 93.3% complete and 95.9% complete+fragmented BUSCO core genes represented from the Metazoa BUSCO database in the final genome. To investigate the distribution of novel genes in Berghia, we compared the predicted proteome from the genome to 49 predicted proteomes obtained from MolluscDB, ENSEMBL, and transcriptome data obtained from the NCBI Sequence Read Archive, which include other nudibranchs, gastropods, and molluscs, and other metazoans. Ultimately, this investigation into gene novelty in Berghia will provide important insights into the impacts of novel genes on mollusc biodiversity.