biostudies-literatureMarinov GKNational Institute of Nursing ResearchNIAID NIH HHSNHGRI NIH HHSNCI NIH HHSNational Institutes of HealthNational Science Foundation65https://www.ebi.ac.uk/biostudies/studies/S-EPMC8887012biostudies-literatureUnknown23(1)<h4>Background</h4>Nucleomorphs are remnants of secondary endosymbiotic events between two eukaryote cells wherein the endosymbiont has retained its eukaryotic nucleus. Nucleomorphs have evolved at least twice independently, in chlorarachniophytes and cryptophytes, yet they have converged on a remarkably similar genomic architecture, characterized by the most extreme compression and miniaturization among all known eukaryotic genomes. Previous computational studies have suggested that nucleomorph chromatin likely exhibits a number of divergent features.<h4>Results</h4>In this work, we provide the first maps of open chromatin, active transcription, and three-dimensional organization for the nucleomorph genome of the chlorarachniophyte Bigelowiella natans. We find that the B. natans nucleomorGenome biologyThe chromatin organization of a chlorarachniophyte nucleomorph genome.PMC8887012U19 AI0572661645164UM1 HG009442UM1HG009442RM1 HG007735RO1 HG008140DP2 CA2280421UM1HG009436U01 HG009431P50 HG0077351DP2OD022870-011U01HG009431R01 HG008140P50HG007735UM1 HG009436U19AI057266Grossman ARHe CGreenleaf WJMarinov GKChen XWu TKundaje AfalseThe chromatin organization of a chlorarachniophyte nucleomorph genome.<h4>Background</h4>Nucleomorphs are remnants of secondary endosymbiotic events between two eukaryote cells wherein the endosymbiont has retained its eukaryotic nucleus. Nucleomorphs have evolved at least twice independently, in chlorarachniophytes and cryptophytes, yet they have converged on a remarkably similar genomic architecture, characterized by the most extreme compression and miniaturization among all known eukaryotic genomes. Previous computational studies have suggested that nucleomorph chromatin likely exhibits a number of divergent features.<h4>Results</h4>In this work, we provide the first maps of open chromatin, active transcription, and three-dimensional organization for the nucleomorph genome of the chlorarachniophyte Bigelowiella natans. We find that the B. natans nucleomor2022-01-01T00:00:00Z2022 Mar2026-05-31T02:37:13.368Z2024-11-20T22:32:32.938ZS-EPMC88870123523246510.1186/s13059-022-02639-5