Heatmap visualization and hierarchical clustering of RNA-sequencing expression data
Expression profiles can be 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, amongst other characteristics. Both samples (columns) and genes (rows) are ordered by hierarchical clustering to reveal their hidden structure. This enables the identification of groups of genes with concordant expression patterns across the samples, and assessment of the heterogeneity of the sample groups.