Fig. 3.

Clustering of tissue regions and miRNAs based on expression profiles of known miRNAs. The heatmap was created using the R function “heatmap” with default parameter setting. Specifically, 1-r was used for measuring the column distance where r was the Pearson correlation between samples. miRNA expression was normalized by total mapped reads in each sample. Colors ranging from dark red to white indicate low to high abundance levels.