Heatmap visualization and hierarchical clustering of RNA-sequencing expression data

Heatmap visualization and hierarchical clustering of RNA-sequencing expression data

Expression profiles are visualized across a sample group using heatmaps like this, in which the expression levels of the genes are indicated by color. The genes can be selected for the figure based on their variance, expression fold change, or function, for example. Both samples (columns) and genes (rows) are ordered by hierarchical clustering to reveal their hidden structure. This enables identifying groups of genes with concordant expression patterns across the samples, and assessing the heterogeneity of the sample groups.