To understand the significance of what GeneChip expression analysis microarrays do, you need to understand the basics of DNA. DNA is a long chain of molecules shaped like a double helix, or a very long spiral staircase. DNA is the genetic blue print, or script, providing instructions for all cellular processes.

Whereas DNA is the script for making ribonucleic acid (RNA) and proteins, RNA directs the production of all proteins including enzymes and the structural proteins that make up our ears, liver, heart, hair and skin.