BACKGROUND Jellyfish belong to the phylum Cnidaria, which occupies an important phylogenetic location in the early-branching Metazoa lineages. The jellyfish Rhopilema esculentum is an important fishery resource in China. However, the genome resource of R. esculentum has not been reported to date. FINDINGS In this study, we constructed a chromosome-level genome assembly of R. esculentum using Pacific Biosciences, Illumina, and Hi-C sequencing technologies. The final genome assembly was ∼275.42 Mb, with a contig N50 length of 1.13 Mb. Using Hi-C technology to identify the contacts among contigs, 260.17 Mb (94.46%) of the assembled genome were anchored onto 21 pseudochromosomes with a scaffold N50 of 12.97 Mb. We identified 17,219 protein-coding genes, with an average CDS length of 1,575 bp. The genome-wide phylogenetic analysis indicated that R. esculentum might have evolved more slowly than the other scyphozoan species used in this study. In addition, 127 toxin-like genes were identified, and 1 toxin-related "hub" was found by a genomic survey. CONCLUSIONS We have generated a chromosome-level genome assembly of R. esculentum that could provide a valuable genomic background for studying the biology and pharmacology of jellyfish, as well as the evolutionary history of Cnidaria.

中文翻译：

---

水母 Rhopilema esculentum 的染色体水平参考基因组。


背景水母属于刺胞动物门，在早期分支的后生动物谱系中占据重要的系统发育位置。海蜇是我国重要的渔业资源。然而，迄今为止，R. esculentum 的基因组资源尚未见报道。结果在这项研究中，我们使用 Pacific Biosciences、Illumina 和 Hi-C 测序技术构建了 R. esculentum 的染色体水平基因组组装。最终的基因组组装大小约为 275.42 Mb，重叠群 N50 长度为 1.13 Mb。使用 Hi-C 技术来识别重叠群之间的接触，将组装的基因组的 260.17 Mb (94.46%) 锚定到 21 条假染色体上，支架 N50 为 12.97 Mb。我们鉴定了 17,219 个蛋白质编码基因，平均 CDS 长度为 1,575 bp。全基因组系统发育分析表明，R. esculentum 可能比本研究中使用的其他舟虫物种进化得更慢。此外，还鉴定出127个类毒素基因，并通过基因组调查发现了1个与毒素相关的“枢纽”。结论我们已经生成了 R. esculentum 的染色体水平基因组组装，可以为研究水母的生物学和药理学以及刺胞动物的进化历史提供有价值的基因组背景。