11 Facts About Genomic imprinting

Genomic imprinting is an epigenetic phenomenon that causes genes to be expressed or not, depending on whether they are inherited from the mother or the father.

Partial imprinting occurs when alleles from both parents are differently expressed rather than complete expression and complete suppression of one parent's allele.

Forms of genomic imprinting have been demonstrated in fungi, plants and animals.

Genomic imprinting is an inheritance process independent of the classical Mendelian inheritance.

Human diseases involving genomic imprinting include Angelman syndrome, Prader–Willi syndrome and male infertility.

Term "Genomic imprinting" was first used to describe events in the insect Pseudococcus nipae.

The researchers were able to succeed by using one egg from an immature parent, thus reducing maternal Genomic imprinting, and modifying it to express the gene Igf2, which is normally only expressed by the paternal copy of the gene.

Also known as the kinship theory of genomic imprinting, this hypothesis states that the inequality between parental genomes due to imprinting is a result of the differing interests of each parent in terms of the evolutionary fitness of their genes.

In support of this hypothesis, genomic imprinting has been found in all placental mammals, where post-fertilisation offspring resource consumption at the expense of the mother is high; although it has been found in oviparous birds where there is relatively little post-fertilisation resource transfer and therefore less parental conflict.

However, our understanding of the molecular mechanisms behind genomic imprinting show that it is the maternal genome that controls much of the imprinting of both its own and the paternally-derived genes in the zygote, making it difficult to explain why the maternal genes would willingly relinquish their dominance to that of the paternally-derived genes in light of the conflict hypothesis.

The Genomic imprinting produces effects similar to the mechanisms in other insects that eliminate paternally inherited chromosomes in male offspring, including arrhenotoky.