Ren Li, Zeng Yiyan, Liu Qizhi, Tu Xiaolong, Chen Fayi, Wu Hao, Wang Chuan, Wu Chang, Luo Mengxue, Tai Yakui, Zhou Hailu, Li Mengdan, Liu Ling, Wu Dongdong, Liu Shaojun
Engineering Research Center of Polyploid Fish Reproduction and Breeding of the State Education Ministry, College of Life Sciences, Hunan Normal University, Changsha, 410081, China.
Yuelushan Laboratory, Changsha, 410081, China.
Sci China Life Sci. 2025 May 23. doi: 10.1007/s11427-024-2868-y.
The remarkable diversity of the Cyprinidae family highlights the importance of hybridization and gene flow in generating genetic variation, adaptation, and even speciation. However, why do cyprinid fish frequently overcome postzygotic reproductive isolation, a mechanism that normally prevents successful reproduction after fertilization? To address this gap in knowledge, we conducted comparative studies using reciprocal F hybrid lineages derived from intergeneric hybridization between the cyprinid species Megalobrama amblycephala and Culter alburnus. Utilizing long-read genome sequencing, ATAC-seq, Hi-C, and mRNA-seq technologies, we identified rapid genomic variations, chromatin remodeling, and gene expression changes in the testicular cells of F hybrid individuals. By analyzing the distribution of these alterations across three gene categories (allelic genes, orphan genes, and testis-specific genes), we found that changes were less pronounced in allelic and testis-specific genes but significantly more pronounced in orphan genes. Furthermore, we hypothesize that rnf212b is a crucial testis-specific gene that regulates spermatogenesis. Our findings suggest that allelic and testis-specific genes potentially mitigate "genomic shock" on reproductive function following hybridization. This research offers potential insights into the formation mechanisms of homoploid hybridization by demonstrating the coordinated interplay of genomic variations, chromatin remodeling, and gene expression changes during testicular development and spermatogenesis.
鲤科鱼类显著的多样性凸显了杂交和基因流动在产生遗传变异、适应甚至物种形成中的重要性。然而，为什么鲤科鱼类经常能克服合子后生殖隔离，而这种机制通常会阻止受精后成功繁殖呢？为了填补这一知识空白，我们使用了源自鲤科鱼类鳙鱼和赤眼鳟属间杂交的正反交F1杂种谱系进行了比较研究。利用长读长基因组测序、ATAC-seq、Hi-C和mRNA-seq技术，我们在F1杂种个体的睾丸细胞中鉴定出了快速的基因组变异、染色质重塑和基因表达变化。通过分析这些变化在三类基因（等位基因、孤儿基因和睾丸特异性基因）中的分布，我们发现等位基因和睾丸特异性基因中的变化不太明显，而孤儿基因中的变化则明显更显著。此外，我们假设rnf212b是一个调节精子发生的关键睾丸特异性基因。我们的研究结果表明，等位基因和睾丸特异性基因可能会减轻杂交后对生殖功能的“基因组冲击”。这项研究通过展示睾丸发育和精子发生过程中基因组变异、染色质重塑和基因表达变化的协同相互作用，为同源多倍体杂交的形成机制提供了潜在的见解。
