Tuesday 20 February 2007
In spotted microarrays, the probes are oligonucleotides, cDNA or small fragments of PCR products corresponding to mRNAs.
This type of array is typically hybridized with cDNA from two samples to be compared (e.g. patient and control) that are labeled with two different fluorophores (e.g. Rhodamine (red) and Fluorescein (green)). The samples can be mixed and hybridized to one single microarray that is then scanned, allowing the visualization of up-regulated and down-regulated genes in one go.
The downside of this is that the absolute levels of gene expression cannot be observed, but only one chip is needed per experiment. One example of a provider for such microarrays is Eppendorf with their DualChip platform.
- oligonucleotide microarrays