Introduction to Large-scale Gene Expression Data Analysis.

The high-density DNA microarray is the most powerful, versatile and widely used tools for gene expression analysis. It is based on the principle of specificity and complimentary hybridization of nucleotide sequences. Thousands of individual nucleic acid species called probes is hybridized with the complex mixture of labeled nucleic acids called target that have a designated spots on a solid surface. The fluorescent-labeled probe fragments bind to their appropriate partners and the intensity of emission can be assessed by an ion laser. The two main microarray technologies that are widely used are oligonucleotide and cDNA arrays.