Imprinted genes are expressed from only one parental allele. ICRs (Imprinting Control Regions) carry parent-specific methylation. CTCF binding creates chromatin loops controlling expression.
Paternal allele
Maternal allele
CpG methylation
CTCF binding site
Active gene
Silenced gene
Genomic Conflict Theory Paternal genome: maximize resource extraction from mother. Maternal genome: conserve resources across offspring. This conflict drives imprinting evolution.