First draft genome for the sand-hopper Trinorchestia longiramus

Crustacean amphipods are important trophic links between primary producers and higher consumers. Although most amphipods occur in or around aquatic environments, the family Talitridae is the only family found in terrestrial and semi-terrestrial habitats. The sand-hopper Trinorchestia longiramus is a talitrid species often found in the sandy beaches of South Korea. In this study, we present the first draft genome assembly and annotation of this species. We generated ~380.3 Gb of sequencing data assembled in a 0.89 Gb draft genome. Annotation analysis estimated 26,080 protein-coding genes, with 89.9% genome completeness. Comparison with other amphipods showed that T. longiramus has 327 unique orthologous gene clusters, many of which are expanded gene families responsible for cellular transport of toxic substances, homeostatic processes, and ionic and osmotic stress tolerance. This first talitrid genome will be useful for further understanding the mechanisms of adaptation in terrestrial environments, the effects of heavy metal toxicity, as well as for studies of comparative genomic variation across amphipods.

端足类甲壳动物（Crustacean amphipods）是初级生产者与高级消费者之间的重要营养联系纽带。尽管绝大多数端足类栖息于水生环境或其周边区域，但跳虾科（Talitridae）是唯一能够在陆地与半陆地生境中生存的端足类类群。沙跳虾（sand-hopper）长肢三跳虾（Trinorchestia longiramus）是韩国沙滩常见的跳虾科物种。本研究首次报道了该物种的草稿基因组组装与注释结果：我们共生成约380.3 Gb的测序数据，最终组装得到大小为0.89 Gb的草稿基因组。注释分析预测得到26080个蛋白质编码基因，基因组完整度达89.9%。与其他端足类的比较基因组分析显示，长肢三跳虾拥有327个独特的直系同源基因簇，其中多个扩张的基因家族参与有毒物质的细胞转运、稳态维持过程以及离子与渗透胁迫耐受。这首个跳虾科基因组将有助于进一步解析陆地环境适应机制、重金属毒性的生物学效应，同时也可为端足类的跨类群比较基因组变异研究提供重要支撑。