imprinting
Definition
Genomic imprinting is an epigenetic phenomenon where certain genes are expressed in a parent-of-origin-specific manner, meaning only one allele (maternal or paternal) is transcriptionally active while the other is silenced. This monoallelic expression is regulated by DNA methylation and histone modifications at imprinting control regions (ICRs). Imprinting affects approximately 150-200 genes in mammals and plays critical roles in fetal growth, placental development, metabolism, and behavior. Aberrant imprinting is associated with developmental disorders like Prader-Willi and Angelman syndromes, as well as various cancers. Unlike typical Mendelian inheritance, imprinted genes violate the principle that maternal and paternal alleles contribute equally to phenotype, making them crucial for understanding complex disease mechanisms and inheritance patterns.
Visualize imprinting in Nodes Bio
Researchers can visualize imprinted gene networks to map parent-of-origin expression patterns across tissues and developmental stages. Network graphs can connect imprinted genes with their regulatory elements, DNA methyltransferases, and downstream targets to reveal imprinting control hierarchies. Integration with disease phenotype data enables identification of imprinting disruptions in developmental disorders and cancers, while pathway analysis reveals how imprinted genes influence metabolic and growth signaling networks.
Visualization Ideas:
- Imprinted gene regulatory networks showing ICRs, methylation sites, and target genes with parent-of-origin annotations
- Multi-tissue imprinting maps displaying tissue-specific monoallelic expression patterns across development
- Disease-imprinting networks linking LOI events to cancer pathways and metabolic disorders
Example Use Case
A cancer genomics team investigating loss of imprinting (LOI) in colorectal tumors uses network analysis to map relationships between hypomethylated ICRs and aberrantly expressed imprinted genes like IGF2 and H19. By integrating methylation data, gene expression profiles, and patient outcomes, they identify a network module where IGF2 overexpression drives proliferation through PI3K/AKT signaling. The visualization reveals that multiple imprinted genes in the 11p15.5 region show coordinated LOI, suggesting a regional epigenetic disruption mechanism that could serve as a therapeutic target.