Fig. 2

Clustering result of homologous genes in E. coli K12 displays in a heatmap, dendrograms, and color bars. The heatmap and dendrogram were generated by hierarchical clustering with average linkage. The heatmap is symmetrical about the diagonal, the more similar two homologs are, the closer the value between them is to 1 (red). The two dendrograms and their color bars on the top and left sides of the heatmap are identical. The vertical distances on each branch of the dendrogram indicate the relatedness of genes. Applying the dynamic tree cut algorithm on the tree, the clusters were formed as shown in the color bars below the dendrograms. The 13 gene clusters are represented in different modules in the color bar