Amplification of GC-rich DNA fragment from whole blood in the presence of various DNA dyes. Human blood was diluted with mouse blood to yield 0, 4, 11, 33 and 100 copies of human Q8N4X1 gene per 1 μl of PCR reaction mix II supplemented with PT enhancer and various DNA dyes. Final concentration of human/mouse blood was 2% in all mixes. The samples were analyzed by qPCR followed by agarose gel electrophoresis and staining with ethidium bromide. Position of the specifically amplified DNA fragment is indicated by an arrow (Fr. 6). Lane L, DNA standard ladder with sizes indicated in kbp on the left. Regression coefficients (R2) and efficiencies (E) were calculated from plots of Cq values versus log copy numbers. All samples were analyzed in 3-4 independent experiments with similar results.