gene amplification


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Gene amplification

The process by which a cell specifically increases the copy number of a particular gene to a greater extent than it increases the copy number of genes composing the remainder of the genome (all the genes which make up the genetic machinery of an organism). It is therefore distinguished from duplication, which is a precise doubling of the genome preparatory to cell division, and endoreduplication, which leads to endopolyploidy.

Gene amplification results from the repeated replication of the deoxyribonucleic acid (DNA) in a limited portion of the genome, in the absence of or to a much greater extent than replication of DNA composing the remainder of the genome. Thus is formed a cell in which the genes composing a limited portion of the genome are present in relatively high copy number, while the genes composing the remainder of the genome are present in approximately normal copy number. See Deoxyribonucleic acid (DNA)

Since gene amplification increases the copy number of a specific region of the genome without altering the copy number of genes composing the remainder of the genome, it would appear to offer an alternative method for developmental control of gene expression. By increasing the number of copies of a particular gene, the number of gene copies available for transcription could thereby be increased.

In a number of instances of gene amplification, the amplification phenomenon appears to be developmentally regulated, and the amplified copies of the gene are subsequently lost from the cell. Studies on cells in culture have demonstrated “amplification” of genes involved in resistance to specific drugs. See Gene, Gene action

gene amplification

[′jēn ‚am·plə·fə‚kā·shən]
(cell and molecular biology)
Any process by which a deoxyribonucleic acid sequence is disproportionately duplicated in comparison with the parent genome.
(genetics)
Repeated replication in a single cell cycle of the deoxyribonucleic acid (DNA) in a limited portion of the genome, resulting in an increase in the number of copies of a particular gene or DNA segment.
References in periodicals archive ?
Her 2/neu gene amplification and over-expression in stomach and esophageal adenocarcinoma: from pathology to treatment.
HER2 gene amplification was determined using the Abbott Molecular Inc (Des Plaines, Illinois), formerly Vysis Inc (Downers Grove, Illinois), Path Vysion HER2 FISH assay, according to the package insert as described.
Our data revealed that HPLC analysis is more accurate than IHC in detection and quantification of ErbB2 gene amplification.
Comparison of dual-color in-situ hybridization and fluorescence in-situ hybridization in HER2 gene amplification in breast cancer.
Conclusion: Although it was reported that hTERC gene amplification may partially contribute to increased telomerase expression and activity in leukemic cells, it is not possible to make such a conclusion based on the results of the this study, as hTERC amplification was not observed in the study group.
The gene amplification activates the oncogenic potential of cellular protooncogenes, which is a reflection of genetic instability of tumor cells and is a particular feature of an aggressive series of tumors (3).
Among these, 26 equivocal cases were assorted and sent for FISH analysis for confirmation of HER2/neu gene amplification.
The HER2 FISH pharmDx Kit is a direct fluorescence in situ hybridization (FISH) assay designed to quantitatively determine HER2 gene amplification and is indicated as an aid in the assessment of patients for whom Herceptin treatment is being considered.
The CISH method has shown a high concordance with fluorescent in situ hybridization (FISH)--based assays for the identification of HER2 gene amplification, now considered the standard for confirming eligibility to receive the drug," Dr.
The CISH method has shown a high concordance with fluorescent in situ hybridization (FISH) based assays for the identification of HER2 gene amplification, now considered the standard for confirming eligibility to receive the drug," said Dr.