Figure 2
E-values of peptides identified by MS/MS in 19 human bone samples searched against a vertebrate database. Boxplots show distributions of E-values of spectra that matched to human peptides (correctly identified) (left) and spectra that matched only to non-human peptide sequences (incorrectly attributed). Width of boxes correspond to the number of spectra in each category, also printed above each box. Incorrectly attributed peptides differ from human consensus sequence peptides by one or more amino acids. These amino acid differences can be isobaric or non-isobaric. A post hoc Tukey test revealed correct peptides and isobaric peptides to be statistically similar and 1 AA and > 1 AA peptides also to be to be statistically similar. All other comparisons were significantly different (p < 0.01).
