expressed sequence tag

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expressed sequence tag (EST)

a partial GENE sequence, usually from the end of a cDNA clone, that is unique to a gene and that can be used to identify it during GENOME analysis. The partial sequence of the cDNA provides a tag to locate the position of the expressed gene (from which mRNA and hence the cDNA is prepared), even though the identity of the gene itself may not be known. See also SEQUENCE TAGGED SITE.