Fig. 4

Sensitivity and specificity analysis of the BEAMing PCR. A decreasing percentage of EGFR mutant DNA was added to the background of the wild-type DNA. Genomic and subsequent BEAMing PCR was carried out. The samples were hybridized and run in a FACSArea III. The mutant (Q1) and wild-type (Q3) populations were separated and are indicated. If the aqueous compartments were all the same size, the expected Poisson distribution was obtained. However, because they are not uniform, some compartments are larger and contain more than one template. This raises the number of double template beads (Q2).