Microarrays can detect differences in gene expression
The key steps in a microarray analysis are (1) extraction of mRNA from cells or tissues, (2) synthesis of fluorescent-dye-labeled cDNA probes, (3) hybridization to the microarray, (4) detection of the fluorescent signal from hybridized probes, and (5) image analysis to identify relative levels of hybridized probe. The relative levels reveal those genes whose expression is increased or decreased under the conditions analyzed.

ANIMATED ART: DNA microarrays: using an oligonucleotide array to analyze patterns of gene expression