(A) Sequence electropherogram for the 185delAG mutant. Peaks are clear before the mutation site and ambiguous beyond the mutation site (after “T” at position 217). (B) Mass spectrum showing the sequencing data for a 185delAG mutant. The first single peak corresponds to a “T” in both alleles, showing there is no mutation up to that point. The deletion of a C and T in one of the two copies (A and G in the forward sequence) in the subsequent two positions causes the appearance of a series of double peaks starting from the second position. The reverse wild-type DNA sequence is 3′-... TCTAAGA... 5′, whereas the mutant DNA sequence is 3′-... TAAGATT... -5′.