Abstract The order Acipenseriformes, which includes sturgeons and paddlefishes, represents “living fossils” with complex genomes that are good models for understanding whole-genome duplication (WGD) and ploidy evolution in fishes. Here, we sequenced and assembled the first high-quality chromosome-level genome for the complex octoploid Acipenser sinensis (Chinese sturgeon), a critically endangered species that also represents a poorly understood ploidy group in Acipenseriformes. Our results show that A. sinensis is a complex autooctoploid species containing four kinds of octovalents (8n), a hexavalent (6n), two tetravalents (4n), and a divalent (2n). An analysis taking into account delayed rediploidization reveals that the octoploid genome composition of Chinese sturgeon results from two rounds of homologous WGDs, and further provides insights into the timing of its ploidy evolution. This study provides the first octoploid genome resource of Acipenseriformes for understanding ploidy compositions and evolutionary trajectories of polyploidy fishes.

中文翻译：

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全基因组测序揭示中华鲟的同源八倍体及其进化轨迹

摘要鲟鱼目包括鲟鱼和白鲟，代表着具有复杂基因组的“活化石”，是了解鱼类全基因组复制（WGD）和倍性进化的良好模型。在这里，我们对复杂的八倍体中华鲟（Acipenser sinensis）进行了测序并组装了第一个高质量的染色体水平基因组，中华鲟是一种极度濒危的物种，也代表了鲟形目中一个鲜为人知的倍性群。我们的结果表明，A. sinensis 是一个复杂的同源八倍体物种，包含四种八价（8n）、一种六价（6n）、两种四价（4n）和一种二价（2n）。考虑延迟重二倍化的分析表明，中华鲟的八倍体基因组组成是两轮同源全基因组测序的结果，并进一步提供了对其倍性进化时间的见解。该研究为了解多倍体鱼类的倍性组成和进化轨迹提供了第一个鲟鱼目八倍体基因组资源。