# The fine art of chromatin folding: Revealing the path of DNA inside mitotic chromosomes

## TL;DR

Two new studies reveal how DNA folds into rod-shaped chromosomes during mitosis using high-resolution techniques.

## Contribution

The studies reconstruct DNA paths in human chromosomes at nanoscale resolution, revealing loop-extruding molecular machines.

## Key findings

- Loop-extruding molecular machines fold chromatin into compact structures during mitosis.
- Microscopy and sequencing approaches reveal similar chromosome organization models.
- Findings challenge traditional views of higher-order chromatin structures.

## Abstract

How chromatin fibers fold into rod-shaped mitotic chromosomes has long been a central question in genome biology. Two new studies now reconstruct the path of DNA in human chromosomes at nanoscale resolution and reveal how loop-extruding molecular machines fold chromatin into compact, rod-shaped structures at the onset of mitosis. Using microscopy- or sequencing-based approaches, respectively, both studies converge on similar models of chromosome organization yet differ in key mechanistic details. The findings further challenge textbook hypotheses of higher-order chromatin structures and reignite the quest for a detailed understanding of genome architecture inside living cells.

How chromatin fibers fold into rod-shaped mitotic chromosomes has long been a central question in genome biology. Two new studies now reconstruct the path of DNA in human chromosomes at nanoscale resolution and reveal how loop-extruding molecular machines fold chromatin into compact, rod-shaped structures at the onset of mitosis. Using microscopy- or sequencing-based approaches, respectively, both studies converge on similar models of chromosome organization yet differ in key mechanistic details. The findings further challenge textbook hypotheses of higher-order chromatin structures and reignite the quest for a detailed understanding of genome architecture inside living cells.