Pharming for Profit: Monsanto Patents Supposedly Safe Method for Growing Food Crops Containing Insulin, Other Drugs

July 29, 2005

On May 10, 2005, the United State Patent and Trademark Office (USPTO) issued patent 6,891,086 for "Plastid Transformation of Brassica". The patent issued to Calgene, a Monsanto company.

The patented technology allows for the "production of human biological proteins (pharmaceutical proteins) from the plant plastid." Examples given include the DNA coding for Human Growth Hormone (hGH), aprotinin (Trasylol), and insulin or insulin precursors. (Trasylol is used to reduce blood loss in patients undergoing heart bypass surgery.)

This technology differs from other means of genetically modifying plants because it only modifies plant plastids, and not the plant's nuclear, or primary, DNA. Plant plastids, such as chloroplasts, are biosynthetic centers that are responsible for photosynthesis and can be used industrially to produce amino acids, complex carbohydrates, fatty acids, and pigments.

The patent is specifically aimed at modifying plants of the genus Brassica. The family of Brassica plants is large and diverse, covering radishes, turnips, rutabagas, cabbages, cauliflower, canola, and kale. Significantly, these are crop plants, as opposed to non-food plants like tobacco which are easier for scientists to manipulate.

The inventors assert that genes expressed in plastids "are not pollen disseminated, therefore, a trait introduced into a plant plastid will not be transmitted to wild-type relatives." In theory, this would alleviate the concerns of many environmental protection groups.

However, according to a study published in Nature Biotechnology, the inventors' claim may not be well-founded. "This supposition [that Brassica plastids cannot be transmitted through pollen] seems reasonable but requires that the maternal parent and environmental conditions have no effect on transmission." The study further suggested that empirical testing is needed to assess the risks of this technology. No such data is cited by the patent.

Dr. Doug Gurian-Sherman, Senior Scientist at the Center for Food Safety, also disagrees with the claim that plastid engineering is environmentally safe. Dr. Gurian-Sherman told Patients not Patents that "many crops transmit chloroplasts or plastids in pollen." Although it is a relatively rare phenomenon, potential contamination could have devastating effects.

Pollen contamination may occur through a process known as recombination. In recombination, genes in the plastid spontaneously migrate to the cell's primary DNA code. After recombination has occurred, the artificially introduced genes can be transmitted to the wild through pollen. Although the significance of recombination in genetically engineered plastids is the subject of debate, at least one case has already been documented. (CY Huang, "Direct measurement of the transfer rate of chloroplast DNA to the nucleus." Nature, 422, 72-76, 2003.)

Our lack of understanding of the biology of plant plastids is not the only problem. Human error can also be a source of contamination. According to a UK study published in Nature Biotechnology, "Seed spillage is inevitable from the oilseed rape (canola) crop during transportation, planting, and harvest." (SE Scott, et al., "Low probability of chloroplast movement from oilseed rape (Brassica napus) into wild Brassica rapa." Nature Biotechnology, 17:390-92.) For example, Prodigene, Inc. was fined more than $3 million in 2002 when its corn, which contained an animal vaccine, contaminated soybean crops in Iowa and Nebraska.

Some biotechnology companies, however, see little danger in the technology. The web site for Chlorogen, Inc. touts the company.s plastid engineering method. "Chlorogen is able to greatly increase the availability of proteins without concern that genes will transfer to other plants via pollen." Perhaps they should be more concerned. Chlorogen creates genetically modified tobacco with human proteins, despite a publication by Chlorogen founder Dr. Henry Daniell which notes that "species such as tobacco have been reported to have ~0.1-0.5% pollen transfer of chloroplast traits." (H Daniell, "Molecular strategies for gene containment in transgenic crops". Nature Biotechnology, 20:581-86, June 2002.)