Is there any difference between genomic imprinting and gametic imprinting?

Question

Or can one use both terms synonymous?

Answer 1

Gametic imprinting is a form of genomic imprinting.

Answer 2

In most cases, the two inherited copies of any gene are either expressed or silenced equally in the genome. Genomic imprinting is a biological phenomenon observed in some genes in which the two inherited copies of the gene have opposite expression patterns. Each of the two inherited copies of the gene is either expressed or silenced, depending on the parental origin of that copy. Whereas in some genes the maternal copy is the one being expressed, the opposite pattern is observed in other genes; i.e., the maternal copy is silenced while the paternal copy is being expressed. In each species, the set of imprinted genes is the same, as well as the relation between parental origin and expression pattern, for each of the imprinted genes.


Embryonic development in mammals is distinct from that in other vertebrates because it depends on a small number of imprinted genes that are specially expressed from either the maternal or paternal genome. Why mammals are uniquely dependent on sexual reproduction and how this dependency is dictated at a molecular level are questions that have been intensively investigated during the past 2 years. Gene inactivation experiments have confirmed predictions that imprinted genes regulate embryonic and placental growth and that DNA methylation is part of the imprinting mechanism. Despite these considerable achievements, the reason why imprinted hemizygosity is used as a mechanism to regulate the intrauterine growth of mammalian embryos remains elusive.