This perspective aims to identify the relationships between the structural and dynamic properties of chromosomes and the fundamental properties of soft-matter systems. Chromatin is condensed into metaphase chromosomes during mitosis. The resulting structures are elongated cylinders having micrometer-scale dimensions. Our previous studies, using transmission electron microscopy, atomic force microscopy, and cryo-electron tomography, suggested that metaphase chromosomes have a multilayered structure, in which each individual layer has the width corresponding to a mononucleosome sheet. The self-assembly of multilayer chromatin plates from small chromatin fragments suggests that metaphase chromosomes are self-organized hydrogels (in which a single DNA molecule crosslinks the whole structure) with an internal liquid-crystal order produced by the stacking of chromatin layers along the chromosome axis. This organization of chromatin was unexpected, but the spontaneous assembly of large structures has been studied in different soft-matter systems and, according to these studies, the self-organization of chromosomes could be justified by the interplay between weak interactions of repetitive nucleosome building blocks and thermal fluctuations. The low energy of interaction between relatively large building blocks also justifies the easy deformation and structural fluctuations of soft-matter structures and the changes of phase caused by diverse external factors. Consistent with these properties of soft matter, different experimental results show that metaphase chromosomes are easily deformable. Furthermore, at the end of mitosis, condensed chromosomes undergo a phase transition into a more fluid structure, which can be correlated to the decrease in the Mg²⁺ concentration and to the dissociation of condensins from chromosomes. Presumably, the unstacking of layers and chromatin fluctuations driven by thermal energy facilitate gene expression during interphase.

这种观点旨在确定染色体的结构和动态特性与软物质系统的基本特性之间的关系。染色质在有丝分裂过程中凝结成中期染色体。所得结构是具有微米级尺寸的细长圆柱体。我们之前的研究，使用透射电子显微镜、原子力显微镜和冷冻电子断层扫描，表明中期染色体具有多层结构，其中每一层的宽度与单核小体片相对应。来自染色质小片段的多层染色质板的自组装表明，中期染色体是自组织的水凝胶（其中单个 DNA 分子交联整个结构），具有内部液晶顺序，由染色质层沿染色体堆叠产生轴。染色质的这种组织是出乎意料的，但是大结构的自发组装已经在不同的软物质系统中进行了研究，根据这些研究，染色体的自组织可以通过重复核小体构建块的弱相互作用之间的相互作用来证明和热波动。相对较大的积木块之间相互作用的低能量也证明了软物质结构容易变形和结构波动以及各种外部因素引起的相变化。与软物质的这些特性一致，不同的实验结果表明，中期染色体很容易变形。此外，在有丝分裂末期，浓缩的染色体经历相变，转变为更加流动的结构，这可能与 Mg 的减少有关。²⁺浓度和染色体上的凝聚素的解离。据推测，热能驱动的层的解体和染色质波动促进了相间的基因表达。