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...

Genomic imprinting is a normal form of gene regulation that causes a subset of mammalian genes to be expressed from one of the two parental chromosomes. Some imprinted genes are expressed from the maternally inherited chromosomes and others from the paternally inherited chromosomes. This means that the maternal and paternal genomes are not functionally equivalent and is the reason why both a ma...

Although numerous imprinted genes have been described in several lineages, the phenomenon of genomic imprinting presents a peculiar evolutionary problem. Several hypotheses have been proposed to explain gene imprinting, the most supported being Haig's kinship theory. This theory explains the observed pattern of imprinting and the resulting phenotypes as a competition for resources between relat...

A gene mediating interactions between mouse mothers and their pups has recently been claimed to support coadaptation rather than the kinship theory of genomic imprinting. This Formal Comment argues that this claim is unfounded.