CRG study finds gene-activation signals conserved while silencing toolkits diverge across eukaryotes

The chemical signals cells use to switch genes on have remained almost unchanged across about 2 billion years of evolution, while the systems used to switch genes off vary sharply across branches of life, according to a Center for Genomic Regulation study reported by phys.org and published in Nature Genetics (DOI: 10.1038/s41588-026-02672-1). Researchers performed a broad comparative analysis of chromatin regulation, including lineages such as discobans, rhizarians, ichthyosporeans, and cryptomonads that have been largely absent from prior work. Senior author Arnau Sebé-Pedrós said instructions for activating genes are essentially the same in a human, a sea anemone, and a soil amoeba, while silencing instructions and controls on elements such as transposons have kept evolving since the last common eukaryotic ancestor. DNA wraps around histone proteins whose chemical tags tell cells which stretches to read or ignore, allowing one genome to produce different cell types. Faults in chromatin regulation underpin many human diseases, including cancers. The tags date back roughly 2 billion years to the Last Eukaryotic Common Ancestor. The team's iChIP2 method labels chromatin from many species with molecular barcodes and reads them in a single experiment. It helped profile 12 histone modifications across 12 phylogenetically diverse species spanning amoebae, fungi, plants, algae, single-celled predators, and animals, some never mapped before.