Genomic imprinting is the
epigenetic phenomenon by which certain
genes are
expressed in a parent-of-origin-specific manner. If the
allele inherited from the father is imprinted, it is thereby silenced, and only the allele from the mother is expressed. If the allele from the mother is imprinted, then only the allele from the father is expressed. Forms of genomic imprinting have been demonstrated in fungi, plants and animals. Genomic imprinting is a fairly rare phenomenon in mammals; most genes are not imprinted.