De novo assembly of the jellyfish, Nemophilema nomurai genome

Abstract

We have successfully generated and assembled a draft genome sequence of the giant jellyfish, Nemopilema nomurai using PacBio RS long-read sequencing technology. Approximately 213-megabase genome of the jellyfish showed very high heterozyogocity. The assembly results showed that the N50 was 2,711,397 bases and the longest contig reached to 8,511,441 bases. A total of 18,528 high-quality protein-coding genes were predicted from 255 assembled scaffolds. The genome of N. nomuraishowed expanded gene families in neurotransmitter transport and metallopeptidase activities, and contracted gene families in nucleosome and chromatin organization. GO enrichment test of the genes involved in the expanded gene families showed the terms of neuron differentiation and regulation of neurogenesis. Also, these genes were significantly enriched in Regulation of actin cytoskeleton pathway by KEGG pathway annotation. The jellyfish genome will also provide us some clues on the molecular regulation of the scyphozoan metamorphosis.