Competition between separated parental genomes in fertilized eggs aids development

Nature, Published online: 29 April 2026; doi:10.1038/d41586-026-01270-9

In fertilized egg cells, the maternal and paternal genomes are enclosed in separate compartments called pronuclei. Experiments in mice reveal that this spatial separation enables parental competition for cytoplasmic factors, which helps to prevent the dysregulation of chemical modifications to DNA-packing proteins and contributes to healthy embryonic development.