1. The array comparative genomic hybridization (aCGH/CMA) technology
The array comparative genomic hybridization (aCGH/CMA) technology. (A) A DNA microarray is usually a microscope slide with a set of short DNA fragments from selected regions of the genome spotted onto a surface. (B) A magnified view of the microarray surface after hybridization. (C) Genomic DNAs from the test (patient) and a control (normal individual of the same gender) samples are differentially labeled using Cy3 and Cy5 dyes, mixed, and hybridized into array. Spots with an equal amount of Cy3 and Cy5 (spot 1) appear yellow, while spots with an extra amount of test DNA look green (spot 2), and spots where amount of a test DNA is decreased appear red (spot 3). (D) Array CGH plot showing a deletion. Probes (black and red dots) are aligned along the X axis according to the physical position on the chromosome (from the short to the long arm). Ratio between the intensity of Cy3 and Cy5 for each probe is calculated and values are placed onto a log2 scale (Y axis). Probes with an equal amount of the test and control DNA (black dots, ratio = 2/2, log2(2/2) = 0) are clustered around a “0” score on the log2 scale. Negative log2 score indicates deletion (red dots, ratio = 1/2, log2(1/2) = −1.0). (E) Array CGH plot showing a complex duplication/ triplication rearrangement. Gain in DNA copy number is seen as positive log2 scores. Blue dots represent duplication (ratio = 3/2, log2(3/2) = 0.58). Green dots (ratio = 4/2, log2(4/2) = 1.0) depict a triplication (total 4 copies of DNA).
Source: Methods of Modern Cytogenetics, Practical Genetics for the Ob-Gyn
Citation: Hogge W, Rajkovic A. Practical Genetics for the Ob-Gyn; 2015 Available at: Accessed: December 31, 2017
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