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. 2004 Feb 24;32(4):e42. doi: 10.1093/nar/gnh039

Figure 2.

Figure 2

Figure 2

Figure 2

Simultaneous genotyping of two SNP sites in homozygous apoE genes by using exonuclease III, nuclease S1 and two PNA probes: (A) ε3/ε3 by PNA(S112A) and PNA(A158C); (B) ε3/ε3 by PNA(S112A) and PNA(A158T) (T–G mismatch); (C) ε2/ε2 by PNA(S112G) (T–G mismatch) and PNA(A158T). Note that mass signals are clearly observable even when there exists a mismatch between the DNA specimen and the PNA probe (see text for details). Reaction conditions: [apoE DNA (203 bp)] = 3.4 µM, [PNA probe] = 5.0 µM, [exonuclease III] = 14 units/µl at pH 8.0 and 37°C for 10 min, and [nuclease S1] = 6 units/µl at pH 4.6 and 20°C for 12 min. Spectra were recorded in a negative ion mode. The small peaks next to the major peaks (designated by crosses) correspond to the adducts with Na+ or K+ ions.