DNA titration using SYBR®Green I and PicoGreen® dyes. PicoGreen® fluorescence (A) and SYBR®Green I fluorescence (B) with bacteriophage λ DNA in absence (black circle, solid line), or presence (dotted lines) of different amounts of detergents: saponin 0.008% + Triton X-100 0.08% (white triangle); saponin 0.008% (white square); Triton X-100 0.08% (white diamonds); Triton X-100 2% (white circle). Background fluorescence, defined as fluorescence detected in the absence of DNA, was subtracted from each data point. Fluorescence is measured as arbitrary units (AU). Data show average from three replicate experiments. Error bars indicate standard deviations. Lines were calculated by linear regression; r2 >0.99.