genomic imprinting

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genomic imprinting

epigenetic process that leads to inactivation of paternal or maternal allele of certain genes susceptible to epigenetic regulation; accounts, among others, for the Angelman and Prader-Willi syndromes.

genomic imprinting

differential expression of a gene or genes as a function of whether they were inherited from the male or the female parent (e.g., a deletion on chromosome 15 that causes Prader-Willi syndrome if inherited from the father causes instead Angelman's syndrome if inherited from the mother).

ge·nom·ic im·print·ing

(jē-nō'mik im'print-ing)
Epigenetic process that leads to inactivation of paternal or maternal allele of certain genes susceptible to epigenetic regulation; accounts, among others, for the Angelman and Prader-Willi syndromes.

genomic imprinting

The concept, derived from an increasing body of compelling evidence, that the expression of some of the genes depends on whether they have been derived from the father or from the mother. It has been shown, for instance, that chromosomal deletion in chromosomes of parental origin may differ in their effect from the same deletion in the homologous chromosome of maternal origin. Many cancers are associated with loss of a particular chromosome derived from a particular parent—usually the mother. The DNA of some genes is modified during the formation of gametes so as to have altered expression and be activated or inactivated.

genomic imprinting

the process whereby certain genes are modified (principally by METHYLATION) during GAMETOGENESIS, resulting in differential expression of parental alleles depending on whether of maternal or paternal origin. The ‘imprinted’ regions of the DNA are generally less active in transcription. Offspring normally inherit one maternal and one paternal copy of their genes, and generally both copies are active. However, expression of certain genes occurs from only one of the two copies, as a result of imprinting of either the maternal or paternal ALLELE at a particular LOCUS. The phenomenon can occur in a variety of organisms. Only a few human genes are imprinted and they tend to be clustered in the genome. Imprinting may have no effect on health and development, but in some cases can cause medical disorders such as Prader-Willi Syndrome and Angelman Syndrome. See also UNIPARENTAL DISOMY.
References in periodicals archive ?
report that this discrimination, called genetic imprinting (SN: 5/2089, p.
Studies have shown that trap-and-haul fish have lower rates of genetic imprinting, important in finding spawning grounds, according to the letter.
Recent discoveries related to genetic expression have led to the development of the new scientific field of epigenetics, which involves genetic imprinting and gene silencing.
It is now widely believed that genetic imprinting and gene silencing are mediated through the histones.
Scientists don't know how much of the human genome is under the influence of genetic imprinting, says Nicholls, now at the University of Florida College of Medicine at Gainesville.
It also may clarify aspects of another mysterious phenomenon, known as genetic imprinting, in which identical genes behave differently depending upon the gender of the contributing parent (SN: 5/20/89, p.
These influences have their roots in the phenomenon of genetic imprinting.
Researchers became increasingly convinced that genetic imprinting accounts for a variety of unusual inheritance patterns (135: 312) and identified the first genetic disease clearly linked to the phenomenon (136: 324).
Moreover, geneticists examining the syndromes' molecular bases say Prader-Willi now appears to be the first concrete example in humans of a poorly understood genetic phenomenon called genetic imprinting, as well as the best evidence yet linking imprinting to human disease (SN: 5/20/89, p.
Scientists have suspected that genetic imprinting -- a difference in gene expression dependent upon which parent contributed that gene -- might play a critical role in fetal and adult development, and may account for the unusual inheritance patterns of some diseases.