What does CGH mean in Human Genome?
This page is about the meanings of the acronym/abbreviation/shorthand CGH in the Medical field in general and in the Human Genome terminology in particular.
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What does CGH mean?
- Comparative genomic hybridization
- Comparative genomic hybridization is a molecular cytogenetic method for analysing copy number variations relative to ploidy level in the DNA of a test sample compared to a reference sample, without the need for culturing cells. The aim of this technique is to quickly and efficiently compare two genomic DNA samples arising from two sources, which are most often closely related, because it is suspected that they contain differences in terms of either gains or losses of either whole chromosomes or subchromosomal regions. This technique was originally developed for the evaluation of the differences between the chromosomal complements of solid tumor and normal tissue, and has an improved resoIution of 5-10 megabases compared to the more traditional cytogenetic analysis techniques of giemsa banding and fluorescence in situ hybridization which are limited by the resolution of the microscope utilized. This is achieved through the use of competitive fluorescence in situ hybridization. In short, this involves the isolation of DNA from the two sources to be compared, most commonly a test and reference source, independent labelling of each DNA sample with a different fluorophores of different colours, denaturation of the DNA so that it is single stranded, and the hybridization of the two resultant samples in a 1:1 ratio to a normal metaphase spread of chromosomes, to which the labelled DNA samples will bind at their locus of origin. Using a fluorescence microscope and computer software, the differentially coloured fluorescent signals are then compared along the length of each chromosome for identification of chromosomal differences between the two sources. A higher intensity of the test sample colour in a specific region of a chromosome indicates the gain of material of that region in the corresponding source sample, while a higher intensity of the reference sample colour indicates the loss of material in the test sample in that specific region. A neutral colour indicates no difference between the two samples in that location.