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 ?
Dr Libert's team proposes that the biological mechanisms of the X chromosome have a strong impact on an individual's genes, known as genetic imprinting, which gives an immunological advantage to females.
Studies also have shown that trap-and-haul fish have lower rates of the critical genetic imprinting that enables them to return to spawning grounds.
Researchers looked at genetic imprinting in 127 individuals with psoriasis--65 women and 62 men drawn from the California Twin Program database--who had at least one child.
The book is a revised edition of Heffner's Human Reproduction at a Glance (2001); changes have been made to chapters on placental structure and function, genetic imprinting and reproductive tract cancers, and HIV infection.
Recent evidence shows that there is an association between the GABAA receptors and alcohol dependence that is modulated by genetic imprinting.
Nevertheless, the effect of genetic imprinting and trinucleotide expansion may be critical in terms of carrying out germ line gene therapy.