Method of amplification of one or more DNA sequences in a DNA containing sample and methods of investigating such samples

method of amplification of one or more DNA sequences in a DNA containing Sample, and methods of investigating Such Samples are provided in which an improved amplification cycling regime is used. The regime features a first phase and a Second phase, the first phase including a denaturation temperature Step, followed by an annealing temperature Step, followed by a corrected annealed primer extension temperature Step, these Steps being followed by an annealing temperature Step, corrected annealed primer extension temperature Step prior to any further denaturation temperature Steps being applied. Increased amplification
from a given number of amplification cycles and maximised sensitivity for the DNA amplification process is achieved as a result.