Figure 1.

Artificial example. The genes ME1, MDH1, FH, ASL, ASS1, CTH, CDO1, CBS and SHMT1 are presented as red boxes. Five KEGG pathway ('urea cycle', 'citrate cycle', 'pyruvate metabolism', 'cysteine metabolism', 'glycine, serine and threonine metabolism') wiring diagrams are manually linked together to demonstrate that all nine genes form a non-interrupted metabolic network.