biostudies-literatureGan XNational Natural Science Foundation of China3444https://www.ebi.ac.uk/biostudies/studies/S-EPMC12655823biostudies-literatureUnknown14(22)Polycomb Group (PcG) proteins, particularly E(z) (Enhancer of Zeste) genes, play essential roles in transcriptional repression and developmental regulation. To investigate their evolutionary history, we conducted a comprehensive comparative genomic analysis of E(z) homologs across green plants. Phylogenetic analysis revealed that E(z) genes are highly conserved, predominantly occurring as single copies in green algae and early land plants. In seed plants, however, E(z) homologs diverged into two major clades, CLF and SWN, likely originating from an ancient duplication predating seed plant diversification. Conserved domain and motif analyses showed that while all E(z) proteins contain the hallmark SET domain, certain lineages also harbor CXC and SANPlants (Basel, Switzerland)Conservation and Divergence of E(z) Genes in Green Plants.PMC1265582332272750Chen ZGan XZhang LChang XfalseConservation and Divergence of E(z) Genes in Green Plants.Polycomb Group (PcG) proteins, particularly E(z) (Enhancer of Zeste) genes, play essential roles in transcriptional repression and developmental regulation. To investigate their evolutionary history, we conducted a comprehensive comparative genomic analysis of E(z) homologs across green plants. Phylogenetic analysis revealed that E(z) genes are highly conserved, predominantly occurring as single copies in green algae and early land plants. In seed plants, however, E(z) homologs diverged into two major clades, CLF and SWN, likely originating from an ancient duplication predating seed plant diversification. Conserved domain and motif analyses showed that while all E(z) proteins contain the hallmark SET domain, certain lineages also harbor CXC and SAN2025-01-01T00:00:00Z2025 Nov2026-07-05T03:18:21.645Z2026-07-05T03:12:27.977ZS-EPMC126558234130459510.3390/plants14223444