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microarray - principals of microarray and its applications (Oct/24/2004 )


I'm Sharon currently doing my degree program.
I have difficulties in understanding the theory and application behind microarray.
So, anyone can help me with these so that I can get started with my project.
Thank you.


Now that's a brodad question. Basically a microarray is a slide containing tightly spotted substrate, often cDNA.
A labelled probe (or mixture) is added to it and after washing hybridization signals are monitored. That's the basis. For applications:
one of the most often used technique is to analyze whole genome expression profiles.
For this cDNAs containing all known genes are spotted on the slide. Then mRNA of the test organism for instance grown under two different conditions (or mutant vs WT) is isolated and labelled (each with own dye, e.g. Cy3 and Cy5) and then hybridized on the slide. After washing first the itensity of probe 1 is measured, then itensity of probe 2. The ratio of expression can then be calculated (after data normalization) and one can identify genes that are differentially expressed under given conditions.
This is just a rough example, but basically anything that normal hybridization assays can show can also be realized in an array experiment.
I recommend checking pubmed for microarray reviews. There are quite a few out there.


You may find helpful info at


You can find Helpful info regarding microarrays at