Issue#30 - Dedication Theme:
Freedom of Information in the Genetically Modified Age
Lack of transparency might be the worst problem of genetically modified foods
Prepared by Julie MARDIN
Agrobacterium tumefaciens -
A soil bacterium that are natural plant parasites. To find suitable environments for themselves they insert genes into plant hosts, which causes them to form a proliferation of cells, or tumors, near the soil level. This natural ability of the bacteria to transfer genetic information is used in genetic engineering as a vector to transport other desired foreign traits. In a sense they are infecting the plant with the desired information. To do this, the bacterial T-DNA (transfer DNA) is cut out of the bacterial plasmid and replaced with the desired foreign gene. It then transfers transgenic DNA to a random site in the plant genome.
Bacillus thuringiensis (Bt) - a soil bacterium used for biological pest control. Particular strains are chosen for particular insects and transferred into the genome of the plant so that it is expressed in each cell. In a process that has been compared to leaky gut and intestinal bowel disease in humans, it causes the gut wall of the insect to break down and allow toxin spores and normal gut bacteria to enter the body, eventually the spores and bacteria proliferate and the insect dies. The naturally occurring toxin has been in use for many years, in organic farming as well, and on this basis the genetically modified version has been hailed to be safe for humans.
Biolistic gun, Particle gun, ‘Gene Gun’ - a procedure used in genetic modification where the genetic information is directly “shot” into plant cells. DNA is bound to tiny particles of gold or tungsten and then “shot” into plant tissue or single plant cells under high pressure. The accelerated particles penetrate both the cell wall and membranes, slowing down as they do so. The DNA separates from the metal and can be integrated into the genetic material inside the nucleus. Used mostly with monocrops like wheat or corn, for which bacterial vectors are less successful. One disadvantage is damage done to cellular tissue.
DiCamba - An herbicide that has been in use since the 1960s, works by mimicking a naturally occurring plant hormone that triggers uncontrolled growth, and subsequent death of the weed. It is being propelled into greater use for the next generation of herbicide-tolerant crops, both as an external spray as well as a genetically engineered resistance trait.
DNA - The term used to describe the chemical make-up of genetic information. Deoxyribonucleic acid. The building blocks of DNA are called “nucleotides”, each made up of a sugar, a phosphate, and a base. These building blocks combine to form a giant molecule comprising two strands of necleotides, the famous “double helix” that is thought to create the ‘blueprint’ as it contains the instructions or information (genes) needed to construct cellular components like RNA and proteins. As the sequencing of the Human Genome project was completed, we have learned that it takes about 22,000 genes to create an estimated 100,000 proteins, which has outdated the model upon which genetic engineering is based, which is built upon a more linear one gene one protein paradigm. In fact, it seems protein-coding genes account for only 1-2% of DNA. The other 95% is yet to be understood.
EPA - Environmental Protection Agency, a US federal agency that is tasked with protecting human and environmental health. They oversee some genetically modified crops, due to the fact that they have pesticides engineered into their make up, such as those incorporating Bt toxin. As well as of course glyphosate containing herbicides, such as Roundup, which is a big part of the GMO system.
Expression - when a gene is ‘switched’ on and is being used to make a protein. The tasks a cell performs depends on which of its genes are being expressed. Transgene expression is the expression of genes from
the foreign organism.
FDA - Food and Drug Administration, the US federal agency responsible for responsible for regulating food, tobacco, dietary supplements, pharmaceuticals, biopharmaceuticals, medical devices, vaccines, electromagnetic radiation emitting devices, cosmetics and veterinary products.
Gene - a basic physical unit of heredity, made up of a sequence of nucelotides along a piece of DNA that encodes RNA, which when translated into proteins, leads to the expression of a hereditary character.
Gene Gun - see Biolistic Gun
Genetically Modified Organism (GMO) - an organism whose genetic material has been transformed by the introduction of genetic material from a foreign organism, outside of the sexual reproduction process, either through viral or bacterial vector, or biolistic gun.
Genome - the full array of genetic information contained in a cell. The human genome, contains 30,000-40,000 genes and has now been sequenced, as have the genomes of around 100 other organisms, including the mouse (max 30,000 genes) and arabidopsis thaliania, or thale crees (25,000 genes)
Glyphosate - the active ingredient in many herbicides in use today, including the most widely used Roundup(TM), manufactured by Monsanto.
Herbicide - a chemical used to kill weeds, wild and competing.
Horizontal Gene Transfer - the passing of genes from one organism to another, sometimes across species, outside of the sexual reproduction process.
Marker Gene - a gene that is used in the genetic modification process to allow scientists to see more easily which plants have taken up the desired trait. These are thus transferred along with the desired target gene. Marker genes that are frequently used are antibiotic resistance genes.
Monocrops - Crops that are grown continuously on the same land year after year for high yield. This type of farming actually reduces the productivity of the soil, as it depletes it of nutrients, and biodiversity, and requires large amounts of water, fertilizer and pesticides. One early example of the instability brought on by monocropping was the Irish Famine of the 1840s which came about when a certain strain of mold wiped out the entire ‘lumper’ variety of potato that the Irish were depending on for their staple diet.
Pesticide - a chemical designed to kill insects.
Plasmid - small circular DNA molecules occurring and replicating in bacteria independent of its chromosomal information, is used as the vector to transport foreign genes into target organisms.
Proteins - molecules composed of amino acids that are responsible for all metabolic processes, such as building muscle, bones, and transporting blood, regulating hormones. We all have a hundred thousand different proteins all formed from just 20 amino acids, whose sequence is defined in the genetic code or DNA. Our genetic code is read and transmitted to the “protein factories” (ribosomes) in the cells, where proteins are then created.
Recombination - the technique of rearranging, cutting out or splicing together of genes to create artificially constructed DNA molecules, or ‘recombinant DNA’.
RNA - Ribonucleic acid, an essential substance for translating genetic information. RNA exists in the form of a single strand, rather than a double helix, and its function is to transport and translate the information stored in the DNA, and also influences gene activity itself.
Roundup(TM) - The No. 1 selling herbicide on the market today, manufactured by Monsanto. Many geneticallly engineered crops are Roundup Ready crops, engineered to be resistant to the spraying of the herbicide Roundup, by having a gene inserted that helps to metabolize the poison. In this way the chemical can be sprayed much more freely over entire fields to deal with unwanted weeds, without killing the crops outright. A growing body of science is accumulating on the dangers of this chemical and its persistence in the environment.
Substantial Equivalence - a concept, first described in an Organization for Economic Cooperation and Development (OECD) publication in 1993, which stresses than an assessment of a novel food, in particular one that is genetically modified, should demonstrate that the food is as safe as its traditional counterpart. This concept has been used as a cornerstone by the FDA, and regulatory bodies around the world, to allow GMO crops to be commercialized without any pre-market testing. Equivalence is said to be based on chemical and nutritional profiles, cursory tests to detect the presence of known toxins, with no exploration of the possibility of new and unknown ones, and is evaluated by industry itself.
Transgene - a gene that has been introduced into the genome of an organism by means of genetic engineering.
2,4-D - an herbicide and pesticide, was part of the formula for Agent Orange, is being promoted again as a solution to glyphosate-resistant superweeds, both as an external application and as the basis for future herbicide tolerant crops
USDA - United States Department of Agriculture, the federal department that administers programs to provide services to farmers (including research and soil conservation, and efforts to stabilize the farming economy). They have oversight over experimental field trials of GMO crops.
Vector - a circular strand of DNA (plasmid) generally obtained from a bacteria or virus. Genes of interest are commonly integrated into a vector and introduced into a bacteria or other organisms. The Agrobacterium tumefaciens is commonly used as a vector for plant genetic transformation
Updated on June 10, 2014.