Gene Expression Arrays

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A gene expression array (or DNA microarray) is a miniature, massively parallel, and semi-automated process that measures levels of gene products (or mRNA or transcripts). The DNA of an organism (cell or cells) is a set of instructions used to direct its existence. A genetic message is transcribed from DNA into mRNA (messenger RNA), then typically translated into protein. By measuring the levels of mRNA, an indirect glimpse can be taken into the functioning of a cell. The relative and absolute levels of the transcripts are called expressions, and this instantaneous set of expressions is called the expression profile. Profiles can be used, for example, to indicate a disease state.

Historical Background

DNA and RNA are bio-molecules that hybridize bonding due to complementary structure. Hybridization has been used for several decades as means of identifying DNA and RNA present in an organism (cell or cells). Until microarray technology was invented,