In the example below, red represents up-regulated genes and blue represents down-regulated genes. Black represents unchanged expression.įigure 12 An example of a heatmap in which genes have been grouped based on their pattern of gene expression. The colour and intensity of the boxes is used to represent changes (not absolute values) of gene expression.
In heat maps the data is displayed in a grid where each row represents a gene and each column represents a sample. This can be useful for identifying genes that are commonly regulated, or biological signatures associated with a particular condition (e.g a disease or an environmental condition) ( 4). The heatmap may also be combined with clustering methods which group genes and/or samples together based on the similarity of their gene expression pattern. Heatmaps and clusteringĪ common method of visualising gene expression data is to display it as a heatmap (Figure 12). Some of the most common methods are discussed below. Many of the methods for visualising and interpreting gene expression data can be used for both microarray and RNA-seq experiments.
Submission of data to a public repository.Biological interpretation of microarray data.