BACKGROUND The king scallop, Pecten maximus, is distributed in shallow waters along the Atlantic coast of Europe. It forms the basis of a valuable commercial fishery and plays a key role in coastal ecosystems and food webs. Like other filter feeding bivalves it can accumulate potent phytotoxins, to which it has evolved some immunity. The molecular origins of this immunity are of interest to evolutionary biologists, pharmaceutical companies, and fisheries management. FINDINGS Here we report the genome assembly of this species, conducted as part of the Wellcome Sanger 25 Genomes Project. This genome was assembled from PacBio reads and scaffolded with 10X Chromium and Hi-C data. Its 3,983 scaffolds have an N50 of 44.8 Mb (longest scaffold 60.1 Mb), with 92% of the assembly sequence contained in 19 scaffolds, corresponding to the 19 chromosomes found in this species. The total assembly spans 918.3 Mb and is the best-scaffolded marine bivalve genome published to date, exhibiting 95.5% recovery of the metazoan BUSCO set. Gene annotation resulted in 67,741 gene models. Analysis of gene content revealed large numbers of gene duplicates, as previously seen in bivalves, with little gene loss, in comparison with the sequenced genomes of other marine bivalve species. CONCLUSIONS The genome assembly of P. maximus and its annotated gene set provide a high-quality platform for studies on such disparate topics as shell biomineralization, pigmentation, vision, and resistance to algal toxins. As a result of our findings we highlight the sodium channel gene Nav1, known to confer resistance to saxitoxin and tetrodotoxin, as a candidate for further studies investigating immunity to domoic acid.

中文翻译：

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扇贝基因丰富的基因组。


背景技术扇贝王（Pecten maximus）分布于欧洲大西洋沿岸的浅水区。它构成了有价值的商业渔业的基础，并在沿海生态系统和食物网中发挥着关键作用。与其他滤食性双壳类动物一样，它可以积累强效植物毒素，并已进化出一定的免疫力。这种免疫的分子起源引起了进化生物学家、制药公司和渔业管理人员的兴趣。调查结果在此，我们报告了该物种的基因组组装，这是作为 Wellcome Sanger 25 基因组计划的一部分进行的。该基因组由 PacBio 读数组装而成，并使用 10X Chromium 和 Hi-C 数据搭建支架。其 3,983 个支架的 N50 为 44.8 Mb（最长支架 60.1 Mb），其中 92% 的组装序列包含在 19 个支架中，对应于该物种中发现的 19 条染色体。总组装跨度为 918.3 Mb，是迄今为止发布的最好的支架海洋双壳类基因组，表现出后生动物 BUSCO 集的回收率为 95.5%。基因注释产生了 67,741 个基因模型。基因内容分析显示，与其他海洋双壳类物种的测序基因组相比，双壳类存在大量基因重复，几乎没有基因丢失。结论 大对虾的基因组组装及其注释基因集为贝壳生物矿化、色素沉着、视觉和藻毒素抗性等不同主题的研究提供了高质量的平台。根据我们的研究结果，我们重点关注钠通道基因 Nav1，该基因已知可赋予石房蛤毒素和河鲀毒素抗性，作为进一步研究软骨藻酸免疫性的候选基因。