Abstract Distant hybridization is an important method for obtaining hybrids with hybrid genomes. In this study, a new type of hybrid culter (BTBT, 2n = 48) was produced by two rounds of backcrossing with an established hybrid lineage of blunt snout bream (Megalobrama amblycephala, BSB, 2n = 48, ♀) × topmouth culter (Culter alburnus, TC, 2n = 48, ♂). Analyses on DNA content, chromosome number, and fertility suggested that BTBT was a bisexual fertile diploid hybrid fish with 48 chromosomes. A survey regarding complete ITS1 of 45S rDNA revealed two types of ITS1 from different genomes (BSB and TC) and chimeric single nucleotide polymorphisms (SNPs) in the BTBT genome. Morphological trait data shown that BTBT was similar in appearance to TC but had a greater body width. Interestingly, the intermuscular bone (IB) count (127.9 ± 2.14) in BTBT exhibited an average 5.70% reduction compared with that (135.2 ± 2.45) in TC. The hybrid culter with improved characteristics provides a good model for producing new hybrid fish by distant hybridization, and the bisexual fertile hybrid culter is expected to serve as a new resource for fish genetic breeding.

中文翻译：

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大鲟(♀)×白鲢(♂)杂交种系的新型杂种培养基的形成

摘要 远缘杂交是获得具有杂种基因组的杂种的重要方法。在本研究中，通过与已建立的钝吻鲷（Megalobrama amblycephala, BSB, 2n = 48, ♀）×顶嘴鳊（Culter alburnus, TC, 2n = 48, ♂)。对 DNA 含量、染色体​​数目和生育力的分析表明，BTBT 是一种具有 48 条染色体的双性能育二倍体杂交鱼。一项关于 45S rDNA 的完整 ITS1 的调查揭示了来自不同基因组（BSB 和 TC）的两种类型的 ITS1 和 BTBT 基因组中的嵌合单核苷酸多态性 (SNP)。形态特征数据显示 BTBT 在外观上与 TC 相似，但具有更大的体宽。有趣的是，肌间骨 (IB) 计数 (127.9 ± 2. 14) 与 TC 中的 (135.2 ± 2.45) 相比，BTBT 中的平均降低了 5.70%。具有改良特性的杂交鱼为远缘杂交生产新型杂交鱼提供了良好的模式，双性能育杂交鱼有望成为鱼类遗传育种的新资源。