Venn diagrams and hierarchical clustering of microarray expression data. Venn diagrams (A-D) show the overlapping expression of miRNAs in related intestinal loci including the common reference. A) 125 miRNAs showed overlapping expression in duodenum, proximal jejunum and the common reference. B) The Venn diagram shows 130 miRNAs that were common in ileum and distal jejunum. C) 124 miRNAs showing overlapping expression were detected in both colonic loci. D) 93 miRNAs were commonly expressed in all analyzed samples. These miRNAs were chosen to perform the hierarchical clustering. E) Figure shows the heatmap of expression data after hierarchical clustering of both samples and genes. The heatmap is based on calculated log ratios between samples and the common reference. Arrows indicate clusters of interest both on gene as well as sample level. Abbreviations: MDMx, apparently novel miRNAs, d, duodenum; pj, proximal jejunum; dj, distal jejunum; i, ileum; ac, ascending colon; tc, transverse colon.