Figure 6.

Detection of a target DNA molecule within foreign DNA fragments with random sequences. Overview of the detection of the target DNA (DNA S2, 55-mer) containing Ds. A Ds-containing DNA fragment (DNA S2, 55-mer, 6 fM) and foreign DNA fragments with random sequences (100-mer, 60 nM) were amplified by 30 cycles of PCR in the presence of FAM-hx-dPxTP and dDsTP. After the amplification, the FAM-labeled PCR products were isolated by the magnetic bead-bound anti-fluorescein antibody, and then were sequenced in the presence of dPa′TP (2 μM). Prior to the antibody isolation, the amplified DNA fragments corresponding to the 55-mer were purified by gel electrophoresis and were also sequenced.