Fig. 3.

Schematic of principle of DNA microarray and DNA chips: The RNA is extracted from a sample and reverse transcription of mRNA yields cDNA. By integrating with fluorescent dyes, fluorescent-tagged cDNA strands are generated. The labelled cDNAs are then placed on the DNA microarray which permits the hybridization of each cDNA to its complementary strand. The laser excitation of the fluorescent-tagged cDNA strands generates signals which are captured as images by the camera. Image analysis through distinct intensity of the color for each spot yields results instantly.