Chloroplasts in plants are thought to have originated from an engulfing event of a photosynthetic bacteria (cyanobacterial ancestor) by a eukaryote. There are many advantages to chloroplast DNA manipulation because of its bacterial origin. For example, the ability to introduce multiple genes (operons) in a single step instead of many steps and the simultaneous expression of many genes with its bacterial gene expression system. Other advantages include the ability to obtain organic products like proteins at a high concentration and the fact that production of these products will not be affected by epigenetic regulation.