Inverse PCR

Polymerase chain reaction (PCR) is widely accepted as one of the most powerful tools in molecular biology capable of amplifying over 106 identical copies of small (few kb), specific DNA regions. It utilizes the thermostability of the enzyme Taq DNA polymerase I, and allows quick and efficient exponential amplification of a target region between known DNA sequences. This removes the need for time‐consuming cloning, although it does have two key limitations. It is only efficient in amplifying relatively small DNA fragments and secondly, but more importantly, PCR can only be used to amplify regions of known DNA sequence. As such, PCR alone cannot be used to amplify DNA sequences adjacent to an unknown sequence, thus making chromosomal walking unfeasible