Correlation between RNA-seq gene expression levels.

<p>Gene expression levels were compared among the 5 islet preparations (cultured under control condition) and between islets and 5 selected background tissues from the Illumina Human Body Map. Only genes with an RPKM>1 in all samples were considered for analysis. For each pair of samples a Pearson correlation coefficient (PCC) was computed from the power-law normalized expression levels (i.e. the RPKM values). (A) Boxplot for each islet sample (called ID1 to ID5) with the PCC values between the individual islet sample and 4 other islet preparations. (B) Heatmap with clustering dendrograms inferred by employing (1 – PCC) as distance function and complete linkage as clustering function, showing a tight cluster of islet preparations.