Colleen M. Nycz

SDA Target Amplification

Strand displacement amplification (SDA) is an isothermal method for targets (Spargo et al., 1996; Walker et al., 1995; 1996 a; b). This method employs a restriction endonuclease which is capable of nicking a hemiphosphorothioate form of its recognition site and a DNA exonuclease deficient poly-merase which is capable of initiating synthesis at a nick and displacing the downstream strand. This method consists of two parts: a target generation process (Figure lA) that makes copies of the target sequence flanked by nickable restriction sites, and the exponential amplification of these modified target sequences (Figure IB) by repeated nicking, strand displacement, and priming of displaced strands.