Figure 1. Cluster dendrogram of miRNA expression profiles demonstrates samples grouped according to their biological origin in the brain of adult male rats.

The dendrogram shows that the samples from five brain regions are grouped according to their biological relatedness, suggesting that the miRNA expression profiles overall contain region-specific information. The branch lengths of the dendrogram are measures of the difference between samples and show that the within-region variability in miRNA abundances is low compared to the between-region variability. Average standard deviations of the regional miRNA expression levels are 0.43 (am), 0.37 (cb), 0.39 (hip), 0.43 (hyp) and 0.47 (sn). am: amygdala; cb: cerebellum; hip: hippocampus; hyp: hypothalamus; sn: substantia nigra.