It is usually useful to inspect the behaviour of each sample and sample group at each of the differentially expressed genes, using a heatmap. This allows visual validation of the consistency of the differentially expressed genes within and between replicates. In addition the genes have been clustered. In simple terms, grouped by the similarity of their expression profiles. This often highlights any sub−patterns within the data. Finally, in order to focus on the pattern of expression, rather than which gene is generically more highly expressed than any other gene, the data has been row standardised with a z−score.
