A gene chip is a highly specialized, stamp-sized piece of glass or plastic that is used to analyze thousands of genes at a time. They are also called DNA chips or DNA microarrays
Gene chips are covered with gridlike patterns of short DNA strands, called probes. Each probe can specifically bind to a different gene sequence. When sample DNA is placed on the chip, researchers can study which probes bind DNA from the sample to determine which genes were present in the sample. Genes from cancerous cells can be analyzed with gene chips to discover which genes are present in the cancerous cells that are not present in healthy cells. Cells can be treated with drugs, and the gene chip can analyze those genes to determine which genes are turned on or off by the drug.
Since there are hundreds of thousands of probes on a gene chip, using a gene chip can be the equivalent of thousands of conventional genetic tests. Gene chips have therefore dramatically accelerated the pace of genetic research.
Gene chips were first brought to market in 1996 by Affymetrix, which refers to them as GeneChips.