Reference DNA mixtures are an analytical resource for evaluating platform linearity and accuracy. A) The table shows the mixing coefficients of each cell line DNA sample (rows) used to create the specified reference DNA mixtures (columns). An optimization procedure was used to select the most diverse samples based on genetic-variant annotation across the 1052-amplicon panel, and the mixing coefficients were set to enrich for variants at <20 percent variant. B) The cumulative distribution function of the percentage of variants (y-axis) captured by the reference DNA mixtures as a function of the expected percent variant (x-axis). The dark box shows that 1/3 of the variants in the mixtures are expected to be present at ≤8% and the lighter box shows that 50% of the variants are expected to be present at ≤16% variant. C) The mean percent variant (y-axis) as a function of the expected percent variant (x-axis) for the 195 expected variant sites across 4 separate sequencing runs using 250 ng DNA input. Each point is the mean and a red vertical line spans the range of the mean ± standard deviation. A small jitter (less than 1%) was added to the expected percent variant (x-axis) in order to minimize over plotting.