text: Many metabolic pathways are of commercial interest. For instance, the production of many antibiotics or other drugs requires complex pathways. The pathways to produce such compounds  can be transplanted into microbes or other more suitable organism for production purposes. For example, the worlds supply of the anti-cancer drug vinblastine is produced by relatively ineffient extraction and purification of the precursors vindoline and catharanthine from the plant Catharanthus roseus', which are then chemically converted into vinblastine. The biosynthetic pathway to produce vinblastine, including 30 enzymatic steps, has been transferred into yeast cells which is a convenient system to grow in large amounts. With these genetic modifications yeast can use its own metabolites geranyl pyrophosphate and tryptophan to produce the precursors of catharanthine and vindoline. This process required 56 genetic edits, including expression of 34 heterologous genes from plants in yeast cells.