Anophelesmosquitoes revealed new principles of 3D genome organization in insects

Chromosomes are hierarchically folded within cell nuclei into territories, domains and subdomains, but the functional importance and evolutionary dynamics of these hierarchies are poorly defined. Here, we comprehensively profiled genome organizations of five Anopheles mosquito species and showed how different levels of chromatin architecture influence contacts between genomic loci. Patterns observed on Hi-C maps are associated with known cytological structures, epigenetic profiles, and gene expression levels. At the level of individual loci, we identified specific, extremely long-ranged looping interactions, conserved for ~100 million years. We showed that the mechanisms underlying these looping contacts differ from previously described Polycomb-dependent interactions and clustering of active chromatin.