Amplification of nucleic acids

A method of performing a non-isothermal nucleic acid amplification reaction, the method comprising the steps of:

• a) mixing a target sequence with one or more complementary single-stranded primers in conditions which permit a hybridization event in which the one or more primers hybridizes to the target, which hybridization event, directly or indirectly, leads to the formation of a duplex structure comprising two nicking sites disposed at or near opposite ends of the duplex;
• and performing an amplification process by;
• b) using a nicking enzyme to cause a nick at each of said nicking sites in the strands of the duplex;
• c) using a polymerase to extend the nicked strands so as to form newly synthesized nucleic acid, wherein extension with the polymerase recreates the nicking sites;
• and
• d) repeating steps (b) and (c) as desired so as to cause the production of multiple copies of the newly synthesized nucleic acid;
• wherein the temperature at which the method is performed is non-isothermal, and subject to shuttling, a plurality of times, between an upper temperature and a lower temperature during the amplification process of steps (b)-(d), and
• wherein at the upper temperature, one of said polymerase or nicking enzyme is more active than the other of said enzymes, such that there is a disparity in the activity of the enzymes, and at the lower temperature the disparity in the activity of the enzymes is reduced or reversed.