Reproducibility of SGH array. ( A ) X,Y Scatter plot of the hybridization values of duplicate probe sets for each cluster for a single sample within the same array. i: 22.2-22, ii: 26.1-23; iii: ( B ) X,Y scatter of the average hybridization values for each cluster of the same strains tested on separate arrays. i: 22.2-22, ii: 26.1-23; iii: 26.4-24. Red lines indicate thresholds used to define presence/absence of clusters. Hybridization values are displayed as log2. The subcluster with the highest value was chosen as the representative of the cluster.