Read the full paper: Domain-autonomous MKLP1 modules divergently regulate mitotic fidelity and polyploidy in a holocentric system

Hallmarks of multicellular eukaryotic genome organization are chromosome territories, compartments, and loop-extrusion-mediated structures, including TADs. However, these are mainly observed in model organisms, and most eukaryotes remain unexplored. Using Hi-C in the silkworm Bombyx mori we discover a novel chromatin folding structure, compartment S, which is “secluded” from the rest of the chromosome. This compartment exhibits loop extrusion features and a unique genetic and epigenetic landscape, and it localizes towards the periphery of chromosome territories. While euchromatin and heterochromatin display preferential compartmental contacts, S domains are remarkably devoid of contacts with other regions, including with other S domains. Polymer simulations show that this contact pattern can only be explained by high loop-extrusion activity within compartment S, combined with low extrusion elsewhere through the genome. This unique, targeted extrusion represents a novel phenomenon and underscores how evolutionarily conserved mechanisms—compartmentalization and loop extrusion—can be repurposed to create new 3D genome architectures. ### Competing Interest Statement The authors have declared no competing interest.

Chromosomal rearrangements are crucial in speciation, acting as barriers to gene flow. Holocentric c

The rate and chromosomal positioning of meiotic recombination significantly affects the distribution

Holocentric karyotypes are assumed to rapidly evolve through chromosome fusions and fissions due to

The hallmarks of chromosome organization in multicellular eukaryotes are chromosome territories (CT)

Read the full paper: Architecture and function of holocentric CENP-A–independent inner kinetochores

The exact function of kinetochore proteins in meiosis remains unclear. Using live imaging of C. elegans oocytes, the authors systematically study the contribution of each kinetochore sub-complex and describe a push-pull mechanism that confers robustness to chromosome segregation.