A method for the amplified analysis of a gene sequence by a Fok I/DNA machine is described. A tailored nucleic acid that includes a recognition sequence for the analyzed gene and a hybridized sequence of the gene itself acting as the "fuel" substrate of the "machine". Upon recognition of the gene by the "fuel" substrate, the autonomous Fok I-induced cleavage of the resulting duplex proceeds, resulting in the duplication of the gene sequence and the horseradish peroxidase mimicking hemin/G-quadroplex DNAzyme as a chemiluminescence reporter. The autonomous duplication of the gene sequence and the catalytic activity of the DNAzyme provide a double amplification path that enables the analysis of target DNA with a detection limit of 1 x 10(-14) M.