Figure 2: Reference fluorescent signatures from normal EGFR exon 18-21 sequences. This figure shows the fluorescent signatures for EGFR exons 18-21 from normal DNAs with different genotypes for the naturally-occurring rs1050171 single-nucleotide polymorphism in EGFR exon 20 (Panel A: exon 18; Panel B: exon 19; Panel C: exon 20; Panel D: exon 21 - normal EGFR sequences in these DNA samples were independently confirmed by sequencing). Each exon generated its own characteristic, highly reproducible fluorescent signature which was the same for all normal DNA samples tested (exons 18, 19, and 21; Panels A, B, and D) except for exon 20 where samples with different SNP rs1050171 allele configurations had unique fluorescent signatures (Panel C). These normal fluorescent signatures served as a reference for comparison against the fluorescent signatures from test samples.