Figure 3. The representative chromatograms of gene dosage PCR. A: A normal female has two copies of the RS1. B: A normal male has one copy of the RS1. C: The chromatogram of case 13 showed one copy of the RS1. Each amplified products from six exons of RS1 is indicated by the arrowhead above the fluorescent peak, and the size of each amplicon is shown below. The ratio calculated from the height of each peak is proportional to the targeted exon dosage, therefore duplication can be ruled out in the case 13. For example, the gene dosage of exon 4 was calculated as 1.0 in normal male, 2.09 in normal female, and 1.05 in case 13. Abbreviations: beta hemoglobin gene (HBB); beta-2-microglobulin gene (B2M).