The sensitivity of variant detection at lower sequencing depths for the targets containing different SNVs. The sensitivity of variant detection (Y axis) was plotted for the targets containing different number of SNVs (different lines) at different average sequencing depths (X axis) based on exome sequencing (A) or simulated data (B). In exome sequencing, the sensitivity of variant detection became decreased with the reduced sequencing depths. At lower sequencing depths, the sensitivity was lower for the targets containing more SNVs. For example, at average depth of 10, whereas a sensitivity of 76.7% was achieved for the targets containing only one SNV, the sensitivity for the targets with four SNVs dropped to 71.2%. Such a trend was not observed for simulated data, implicating the decreased sensitivity was largely due to capture bias.