Spectral Clustering co-occurrence plot.

<p>Participants are ordered along both X- and Y-axis according to the co-occurrence score (i.e. the more similar the peptide profiles of any two participants, the higher their tendency to cluster together and the closer they are placed on the axis). Co-occurrence score values range from 0 (for participants who never cluster together) to 1.0 (for participants who always cluster together). The horizontal bar delimits the four clusters.