Wang Yubo, Zhao Lulu, Wang Deyan, Chen Kai, Luo Tiannan, Luo Jianglin, Jiang Chengzhi, He Zhoujian, Huang Heng, Xie Jiaxiao, Jiang Yuanzhong, Liu Jianquan, Ma Tao
Key Laboratory for Bio-Resource and Eco-Environment of Ministry of Education & Sichuan Zoige Alpine Wetland Ecosystem National Observation and Research Station, College of Life Science, Sichuan University, Chengdu, China.
School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 610054, China.
Genome Biol. 2025 May 2;26(1):111. doi: 10.1186/s13059-025-03578-7.
Centromeres play a crucial role in maintaining genomic stability during cell division. They are typically composed of large arrays of tandem satellite repeats, which hinder high-quality assembly and complicate our efforts to understand their evolution across species. Here, we use long-read sequencing to generate near-complete genome assemblies for two Populus and two Salix species belonging to the Salicaceae family and characterize the genetic and epigenetic landscapes of their centromeres.
The results show that only limited satellite repeats are present as centromeric components in these species, while most of them are located outside the centromere but exhibit a homogenized structure similar to that of the Arabidopsis centromeres. Instead, the Salicaceae centromeres are mainly composed of abundant transposable elements, including CRM and ATHILA, while LINE elements are exclusively discovered in the poplar centromeres. Comparative analysis reveals that these centromeric repeats are extensively expanded and interspersed with satellite arrays in a species-specific and chromosome-specific manner, driving rapid turnover of centromeres both in sequence compositions and genomic locations in the Salicaceae.
Our results highlight the dynamic evolution of diverse centromeric landscapes among closely related species mediated by satellite homogenization and widespread invasions of transposable elements and shed further light on the role of centromere in genome evolution and species diversification.
着丝粒在细胞分裂过程中对维持基因组稳定性起着至关重要的作用。它们通常由大量串联卫星重复序列组成，这阻碍了高质量组装，并使我们理解其跨物种进化的努力变得复杂。在这里，我们使用长读长测序技术为杨柳科的两个杨树物种和两个柳树物种生成近乎完整的基因组组装，并对它们着丝粒的遗传和表观遗传景观进行表征。
结果表明，在这些物种中，只有有限的卫星重复序列作为着丝粒成分存在，而它们中的大多数位于着丝粒之外，但呈现出与拟南芥着丝粒相似的同质化结构。相反，杨柳科着丝粒主要由丰富的转座元件组成，包括CRM和ATHILA，而LINE元件仅在杨树着丝粒中被发现。比较分析表明，这些着丝粒重复序列以物种特异性和染色体特异性的方式广泛扩展并与卫星阵列穿插，推动了杨柳科着丝粒在序列组成和基因组位置上的快速更替。
我们的结果突出了由卫星同质化和转座元件的广泛入侵介导的密切相关物种之间多样化着丝粒景观的动态进化，并进一步阐明了着丝粒在基因组进化和物种多样化中的作用。
