Centromeres attach chromosomes to spindle microtubules during cell division and, despite this conserved role, show paradoxically rapid evolution and are typified by complex repeats. We used long-read sequencing to generate the Col-CEN Arabidopsis thaliana genome assembly that resolves all five centromeres. The centromeres consist of megabase-scale tandemly repeated satellite arrays, which support CENTROMERE SPECIFIC HISTONE H3 (CENH3) occupancy and are densely DNA methylated, with satellite variants private to each chromosome. CENH3 preferentially occupies satellites that show the least amount of divergence and occur in higher-order repeats. The centromeres are invaded by ATHILA retrotransposons, which disrupt genetic and epigenetic organization. Centromeric crossover recombination is suppressed, yet low levels of meiotic DNA double-strand breaks occur that are regulated by DNA methylation. We propose that Arabidopsis centromeres are evolving through cycles of satellite homogenization and retrotransposon-driven diversification.

中文翻译：

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拟南芥着丝粒的遗传和表观遗传景观


着丝粒在细胞分裂过程中将染色体附着在纺锤体微管上，尽管其作用保守，但其却表现出矛盾的快速进化，并以复杂的重复序列为代表。我们使用长读长测序来生成 Col-CEN拟南芥基因组组装，可解析所有五个着丝粒。着丝粒由兆碱基级串联重复卫星阵列组成，支持着丝粒特异性组蛋白 H3 (CENH3) 占据，并且 DNA 高度甲基化，每条染色体都有专用的卫星变体。 CENH3 优先占据显示出最少发散量并出现在高阶重复中的卫星。着丝粒被ATHILA逆转录转座子侵入，破坏遗传和表观遗传组织。着丝粒交叉重组受到抑制，但受 DNA 甲基化调节的减数分裂 DNA 双链断裂水平较低。我们认为拟南芥着丝粒是通过卫星同质化和反转录转座子驱动的多样化循环而进化的。