The barred knifejaw, Oplegnathus fasciatus, is characterized by an X₁X₂Y system with a neo-Y chromosome for males. Here, a chromosome-level genome was assembled to investigate the origin of neo-Y chromosome to the male O. fasciatus. Twenty-three chromosomes corresponding to the male karyotypes were scaffolded to 762-Mb genome with a contig N50 length of 2.18 Mb. A large neo-Y chromosome (Ch9) in the male O. fasciatus genome was also assembled and exhibited high identity to those of the female chromosomes Ch8 and Ch10. Chromosome rearrangements events were detected in the neo-chromosome Ch9. Our results suggested that a centric fusion of acrocentric chromosomes Ch8 and Ch10 should be responsible for the formation of the X₁X₂Y system. The high-quality genome will not only provide a solid foundation for further sex-determining mechanism research in the X₁X₂Y system but also facilitate the artificial breeding aiming to improve the yield and disease resistance for Oplegnathus.

禁止的下颌骨Oplegnathus fasciatus的特征是X ₁ X ₂ Y系统，男性具有新Y染色体。在这里，组装了一个染色体水平的基因组，以研究新的Y染色体起源于男性筋膜蛇。将对应于雄性核型的二十三个染色体固定到762-Mb基因组上，其重叠群N50长度为2.18 Mb。男性fasciatus基因组中的一个大的新Y染色体（Ch9）也被组装，并与女性染色体Ch8和Ch10具有高度的同一性。在新染色体Ch9中检测到染色体重排事件。我们的研究结果表明，acrocentric染色体Ch8和Ch10的中心融合应该负责X ₁ X ₂ Y系统的形成。高质量的基因组不仅为进一步在X ₁ X ₂ Y系统中确定性别的机制提供了坚实的基础，而且还有助于旨在提高Oplegnathus产量和抗病性的人工育种。