Validation of selected barley and wheat expression profiles via QPCR. A comparison of logarithmic fluorescence intensities, as measured on the microarrays, with logarithmic QPCR expression levels is shown. Barley data is shown in Panel A and wheat data in Panel B. Four wheat and four barley sequences where the average microarray fluorescence intensity for wheat is greater than barley give rise to the expression levels labelled by "W" (This comparison is carried out individually for each of the eleven tissues, hence there are a total of 44 points marked "W"). Three wheat and four barley sequences where the microarray fluorescence intensity for wheat is less than barley are marked by "B". Plain black data points indicate five sequence pairs where the microarray fluorescence intensities for wheat and barley are comparable. Data from these five sequence pairs were used to generate a calibration curve between the QPCR and microarray data in the form of a straight line fit (solid line) and associated 95% single prediction confidence limits (shaded region).