Method for synthesizing dna strand

A primer extension reaction method for structure-independent amplification of DNA comprising

• preparing a reaction mixture containing the sample DNA, primers, one or multiple enzymes capable of synthesizing a nucleic acid strand complementary to the original nucleic acid strand, such as a thermostable DNA polymerase mixture of dNTPs, and a buffer,
• denaturing the DNA in a denaturation step,
• annealing the primers in an annealing step,
• extending the annealed primers in an extension step to obtain amplified DNA, wherein in the extension step the temperature first rises from the annealing temperature to first extension temperature in the range of 70-90° C., then fluctuates up to second higher extension temperature in the range of 75-95° C. and back down to the first lower extension temperature for a plurality of cycles to destabilize the secondary structures in the DNA to allow the extension.