Cambridge Bioscience offers access to two services from Cell Guidance Systems for human samples based on aCGH and AGH array platforms.
Why perform array hybridisation?
Array platforms offer high-resolution analysis which allows for the detection and reporting of abnormalities that would be missed by G-banding. A much higher resolution of DNA dosage imbalances and loss of heterozygosity (LOH) can be characterised using array comparative genome hybridisation (aCGH) and array genome hybridisation (AGH).
Performed on the Agilent® 8x60K platform, this system utilises two differentially labelled DNA samples cohybridised to an array with ~55,000 oligonucleotide probes. The relative abundance of DNA binding to each probe provides a direct measure of relative copy number of the two samples.
1. A single sample is hybridised against a control DNA sample provided by Cell Guidance Systems
2. Both test and control samples are provided by the customer and are co-hybridised to assess acquired CNV. It is recommended that both the control and test DNA samples are isolated from the cells at the same time
AGH is performed using Affymetrix™ CytoScan™ 750K platform, where the hybridisation data from a single test DNA is compared with a series of controls hybridisations in silico. The array has 750,486 distinct features. The AGH assay is particularly useful for assessing for acquired LOH.
What types of abnormalities are reported?
• Acquired CNVs and LOH present in at least ~15-20% of cells
• For the CytoScan™ platform (AGH), an assessment of normal variation is made with reference to ~5,000 normal control samples and a database of ~10,000 clinical samples. Benign constitutional (heritable) CNVs will not be reported
• Balanced rearrangements and low level (10–20 percent) of mosaicism will not be detected using either CGH or AGH arrays - this level of mosaicism is statistically similar to the level which can be detected by an analysis of 20 cells
Karyotype analysis can detect certain acquired abnormalities, e.g. gain in the small arm of a chromosome, but the precise nature of certain unbalanced chromosomal abnormalities is difficult to establish only by using G-banding analysis. Marker chromosomes and additional material on a chromosome from unknown origin will require array analysis.
Sample types accepted for CGH / AGH services
Human samples - detailed instructions on sample preparation will be provided upon ordering.
Reports will be provided within 15–17 business days which includes the array profile overview, details of any abnormalities detected, and a description of the analysis carried out.
To discuss a project, please contact our Cell Guidance Systems specialist
Material available for download:
Requisition form and instructions to send samples.pdf
Agilent is a registered trademark of Agilent Technologies. Affymetrix and CytoScan are trademarks of Thermo Fisher Scientific.