The biotechnology used in the creation of genetically modified crops is being expanded to encompass the bioengineering of plants that contain therapeutically important proteins and molecules that can be utilized in the manufacturing of pharmaceutical drugs. Often termed "pharming" (a blending of the words pharmaceutical and farming), this process allows scientists to transform a plant's genome via the insertion of a foreign deoxyribonucleic acid (DNA) molecule that carries the genetic information for a pharmaceutical substance. Once the new DNA is inserted, the cultivated plant can produce (by use of its inherent protein-making machinery) large quantities of active pharmaceutical ingredients. Then, these ingredients can be extracted from the plant and processed into a pharmaceutical formulation that has medical application. Specific products include medicinal drugs, vaccines, therapeutic proteins, antibiotics, antibodies, and diagnostic compounds. In other words, the methodology creates a scenario in which farmed plants and crops act as miniature bioreactors or factories to produce pharmaceuticals in an efficient and economically viable manner. See also: Agricultural science (plant); Biologicals; Biotechnology; Deoxyribonucleic acid (DNA); Genetic engineering; Genetically engineered plants; Genetically modified crops; Medicine; Pharmacology; Pharmacy; Protein
For the process of pharming to be successful, particular genes that code for pharmaceutically active proteins must first be identified and isolated. Following incorporation into the genetic material of the plant, these genes (called transgenes) work within the plant to synthesize the pharmaceutical proteins. Finally, after harvesting the plant, the drug substance is extracted and purified, and it can then be used to manufacture a commercial pharmaceutical product. In general, the pharmaceuticals targeted for pharming have been produced by cultures of transgenic plant cells. Although transgenes have been inserted into animal, bacterial, and yeast cells, plants provide faster and much higher yields, as well as being a less expensive means of production. The most common crops involved in pharming are corn, tobacco, and rice. See also: Corn; Engineered minichromosomes in plants; Gene; Rice; Tobacco; Transgenic plant vaccines
Despite the fact that genetic engineering of plants and crops is regulated carefully, there are both known and unknown risks involved with the technique. For example, crops that have been genetically modified for pharmaceutical purposes might accidentally cross-breed with standard food crops, providing an opportunity for unwanted chemical substances to enter the environment and, ultimately, the food chain of many organisms, including humans. Therefore, containment of the transgenes and the crop is of paramount importance. As an alternative, researchers are seeking other pharming techniques that would not involve direct alteration of the cultivated plant's DNA. One such method involves spraying genetically modified viruses on the unmodified recipient plant. The virus is then incorporated into the plant, where the intended pharmaceutical substance can be produced. The benefit in this case is that the DNA of the plant remains unchanged, eliminating the risk of unintentional spreading of the genetically altered material. Still, the application of any genetic engineering technique, whether it involves the modification of the genome of a plant or a virus, is controversial, and many bioethical concerns have been raised with regard to the pharming of crops. See also: Bioethics; Breeding (plant); Environmental toxicology; Pharmaceutical residues in the environment; Public health