2026年9月23日，德国马克斯·普朗克植物育种研究所Korbinian Schneeberger研究团队在《自然》杂志发表论文，宣布他们提出了拟南芥着丝粒的突变动力学。

着丝粒对于细胞分裂过程中染色体的忠实分离至关重要。然而，尽管其功能保守，许多着丝粒含有高度可变但内部高度均一化的串联重复阵列，其演化动态仍知之甚少。在此，研究人员利用突变积累株系的重复基因组组装，定义了拟南芥的着丝粒特异性突变谱。研究人员发现，千碱基大小的插入缺失突变频繁发生，并通过仅添加或移除完整重复单元来持续保持串联重复阵列。点突变的积累速率比基因组其他位置几乎高十倍，可能由紧密连锁的重复单元之间的非等位基因转换驱动。这些发现表明同源定向DNA修复在着丝粒演化中起核心作用，进一步得到以下支持：在抗重组解旋酶RTEL1缺陷的拟南芥株系中，更频繁且更长的保留串联重复的插入缺失发生积累。以观察到的突变谱为参数的正向时间模拟表明，仅千碱基大小的插入缺失和点突变就足以产生天然着丝粒特有的兆碱基大小均一化重复块。总之，研究结果表明，着丝粒演化由同源定向DNA修复塑造的独特突变谱驱动，为理解突变过程如何生成和维持着丝粒DNA的大规模结构提供了定量框架。

附：英文原文

Title: The mutational dynamics of the Arabidopsis centromeres

Author: Dong, Xiao, Jiao, Wen-Biao, Goldkuhle, Lara, Rabanal, Fernando, Amar, Samija, Parker, Matthew T., Campoy, Jos A., Tao, Yueqi, Huettel, Bruno, Ton, Jurriaan, Smith, Lisa M., Puchta, Holger, Weigel, Detlef, Schneeberger, Korbinian

Issue&Volume: 2026-09-23

Abstract: Centromeres are essential for faithful chromosome segregation during cell division. Yet despite their conserved function, many centromeres contain highly variable but internally remarkably homogenized tandem-repeat arrays1,2,3,4,5 whose evolutionary dynamics remain poorly understood. Here, using replicated genome assemblies of mutation accumulation lines, we define the centromere-specific mutation spectrum in Arabidopsis thaliana. We find that kilobase-sized insertion–deletion mutations (indels) occur frequently and consistently preserve tandem-repeat arrays by adding or removing only complete repeat units. Point mutations accumulate at an almost tenfold higher rate than elsewhere in the genome, probably driven by non-allelic gene conversion between closely linked repeat units. These findings suggest a central role for homology-directed DNA repair in centromere evolution, further supported by the accumulation of more frequent and longer tandem-repeat-preserving indels in Arabidopsis lines that are deficient in the anti-recombinase helicase RTEL1. Forward-in-time simulations parameterized with the observed mutation spectrum show that kilobase-sized indels and point mutations alone are sufficient to generate the megabase-sized homogenized repeat blocks characteristic of natural centromeres. Together, our results show that centromere evolution is driven by a distinct mutational spectrum shaped by homology-directed DNA repair, providing a quantitative framework for understanding how mutational processes generate and maintain the large-scale architecture of centromeric DNA.

DOI: 10.1038/s41586-026-11046-w

Source: https://www.nature.com/articles/s41586-026-11046-w