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DNA arrays for low gene expression ? - (Jul/25/2004 )

Hello,

Has anyone some experience in the validity of using micro or macroarray techniques to detect weak gene expression levels? in other word, are DNA arrays suitable to study a low gene expression levels ? which is the more convenient and sensitive methode to measure a low gene expression?

any idea would be appreciated.
thanx

-mybioweb2-

Hello,

In microarray experiment, reliable measurement is more achievable for highly expressed genes in a target sample than for those expressed at low levels. Accurate measurement of low-expressing genes is challenging because the low-intensity signals are not only weaker, but also more variable

Actually, compared to non-PCR based detection such as Northern and RPA, PCR amplification in microarray introduces a bias toward boosting the presence of low copy number genes in the resulted cDNA population.

Generally speaking, oligonucleotide-based DNA microarrays is better than cDNA based microarray for detecting low expression genes, because the generation of cDNA microarrays involves many laborious and error-prone steps, including bacterial culturing, PCR amplification and purification, and DNA sequence validation. In addition, cDNA microarrays are prone to cross-hybridization with gene family members that have 70% or more sequence homology. Long oligonucleotide microarrays perform better than short ones for the same purpose.

Also read this paper:
Optimization of oligonucleotide-based DNA microarrays
http://nar.oupjournals.org/cgi/content/full/30/11/e51

-labrat-