Fig. 6. Correlation of duplicate spots’ intensities on arrays. Intensities (in arbitrary units) from duplicate spots on filters were plotted against each other in excel spreadsheets. A linear trendline was fitted whose equation is displayed on the plots. The correlation coefficient (slope of the trendline) is shown in bold for each plot. (a) Correlation of duplicate spots on a nylon array hybridized for the second time. (b) Correlation of duplicate spots on a polypropylene array hybridized for the third time. (c) Correlation of medium- to low-intensity duplicate spots from b comprising » 85% of the total ORFs. (d) Correlation from b excluding two outliers of the high-intensity duplicate spots.