The overlaps of peptide datasets identified with the UStags, SEQUEST, and Mascot methods. (A)–(C) respectively represent overlaps of UStags peptide datasets, SEQUEST peptide datasets, and Mascot peptide datasets; (D)–(E) represent overlaps among UStags, SEQUEST, and Mascot peptide datasets identified with specific mass tolerances. The peptide datasets shown in Figure 6 are used for this examination.