ABSTRACT
There are currently three types of microarray platforms: cDNA, long oligonucleotide, and short oligonucleotide [3]. For cDNA microarrays, PCR amplicons are printed onto coated glass slides and typically hybridized with two separate cDNA probes labeled with different fl uorescent dyes. Differentially expressed genes are identifi ed by the ratio of dye intensities for each spot. cDNA microarrays can be manufactured “in house” or through organizations such as COGEME (Resources box). For long oligonucleotide microarrays, oligonucleotides of 50-80 bases are printed onto coated glass slides and hybridized with fl uorescently labeled cDNA probes. Long oligonucleotide microarrays have now been made available for Aspergillus fumigatus and Aspergillus nidulans and can be obtained from the PFGRC (Resources box). For short oligonucleotide microarrays, oligonucleotides of 25-30 bases are synthesized in situ using photo-chemistry. Short oligonucleotide microarrays are currently manufactured by Affy metrix (GeneChips) and Nimblegen and are hybridized using a single biotinylated cRNA probe.
