Fig. 2

Distribution, variety, and frequency of fusion events in riboflavin biosynthesis. Riboflavin gene fusions and identification are given in (Additional file 1: Tables S2 A and B). Pathway enzymes are shown as yellow boxes and their abbreviations are given in the central bottom panel. The domain name is given in parentheses inside each yellow box. Fusion partners are listed in the white boxes immediately below the corresponding pathway enzyme. Of these, domains of the riboflavin pathway are in black font and unknown domains or domains belonging to other pathways are in blue font. Compounds are shown in ovals. Their abbreviations are given in the left bottom panel. Highly reactive compounds are marked with a red oval. Participation in triple fusion events is flagged with colored squares inserted in the white boxes of the corresponding enzymes. The identification code for these squares is given in the bottom right panel. The variety of fusions of each riboflavin gene is shown on the top left insert. This variety is represented by a color range where the number of binary fusion events in which each gene participates (see Additional file 1: Table S2B), is proportional to the orange color intensity. The frequency of fusions of each riboflavin gene is displayed on the top right insert. This frequency is expressed as a percentage and it was calculated as described in Methods. It is represented by a color range where the ratio for each riboflavin gene mentioned above is proportional to the blue color intensity. Enzymes that participate in only a few fusions are colored grey in both inserts