[cDNA subtraction].

A difference cloning method and a technique for comparison of two closely related cell types, e.g. a differentiated or transformed cell (tester) and the undifferentiated or normal cell (driver). Driver RNA is converted to double-strand cDNA, usually with the incorporation of a tagged nucleotide, while the tester RNA is converted to first-strand cDNA (with no tag). T he two preparations are mixed, melted and annealed to form, among other species, heteroduplexes composed of one strand from each of the different sources. T he annealed heteroduplexes, as well as other driver species are captured by the tagged nucleotide and removed from the mixture. T he resulting pool will be enriched for those cDNA species unique to the tester cells. Following second-strand synthesis, the double-stranded cDNAs are cloned. T he resulting cDNA library will be enriched for sequences expressed only in the tester cells. cDNA subtraction can also be done by PCR. (NCI/OSP) Qeios · Definition, February 2, 2020