What is mammalian imprinting?

Genomic imprinting, an epigenetic gene-marking phenomenon that occurs in the germline, leads to parental-origin-specific expression of a small subset of genes in mammals. Imprinting has a great impact on normal mammalian development, fetal growth, metabolism and adult behavior.

What is the evolutionary importance of imprinting?

For the sexual antagonism theory, imprinting mitigates intralocus sexual conflict by allowing each sex to approach more closely its sex-specific phenotypic optimum. The requirement for the evolution of imprinted expression under this theory is simple: sex-specific selection pressure on a gene.

What is imprinting in evolution?

Genomic imprinting is an epigenetic phenomenon in which the expression of a gene copy inherited from the mother differs from that of the copy inherited from the father. Many imprinted genes appear to be highly interconnected through interactions mediated by proteins, RNA, and DNA.

What happens if the maternal allele of Igf2r is imprinted?

Mammalian maternal Igf2r allele expression exceeds the paternal allele due to imprinting (silencing). Igf2r null-allele maternal transmission results in placenta and heart over-growth and perinatal lethality (>90%) due to raised extra-cellular IGF2 secondary to impaired ligand clearance.

How does imprinting happen?

Genomic imprinting occurs when two alleles at a locus are not functionally equivalent and is considered the primary epigenetic phenomenon that can lead to the manifestation of parent-of-origin effects [4].

Does imprinting occur in humans?

Imprinting in Humans Imprinting does not appear to be as time-sensitive and context-limited in humans as it is in some other animals. Instead, developmental psychologists generally talk about critical stages of development during which it is much more likely that a child will learn something.

What is kinship theory of imprinting?

The kinship theory of genomic imprinting proposes that parent-specific gene expression evolves at a locus because a gene’s level of expression in one individual has fitness effects on other individuals who have different probabilities of carrying the maternal and paternal alleles of the individual in which the gene is …

Which genes are imprinted?

Two major clusters of imprinted genes have been identified in humans, one on the short (p) arm of chromosome 11 (at position 11p15) and another on the long (q) arm of chromosome 15 (in the region 15q11 to 15q13).

Does imprinting change the DNA sequence?

​Genetic Imprinting Unlike genomic mutations that can affect the ability of inherited genes to be expressed, genomic imprinting does not affect the DNA sequence itself. Instead, gene expression is silenced by the epigenetic addition of chemical tags to the DNA during egg or sperm formation.