Putative metabolic pathways in the marine diatom Phaeodactylum tricornutum investigated by us through isotope-assisted metabolic pathway analysis. This metabolic network includes 10 metabolic pathways distinguished by line color. Metabolic Models I-IV in Fig. 2 consist of different combinations of these pathways. Open circles represent amino acids detected in cell hydrolysates, whose isotope labeling patterns were used in isotope-assisted metabolic pathway analysis. Amino acids are connected to their metabolic precursor(s) by dotted lines. Genes encoding proteins catalyzing all reactions in these pathways were found in the P. tricornutum genome annotation. For more detail and an analysis of all models, see our publication.