DNA microarray: Difference between revisions

Revision as of 02:07, 1 July 2003

Revision as of 02:07, 1 July 2003

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A '''gene chip''' is a piece of glass or plastic on which pieces of DNA, which are referred to as "probe sequences," have been affixed in a microscopic array. Machines use such chips to simultaneously screen a single biological sample for the presense of many [[genetic sequence]]s.

Because '''GeneChip''' is a trademarked name owned by [[Affymetrix]], scientists tend to speak and write about "gene chips" only in reference to the chips that Affymetrix makes. Brought to market in [[1996]], these were the first to come into use, and they are referred to generically as '''oligonucleotide arrays,''' because the probe sequences are short pieces of DNA about 10 to 50 [[nucelotidenucleotide]]s long. A related term is '''microarray''', which refers to a chip that uses much longer probe sequences representing whole or (typically whole [[cDNA]]s).

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.