Genetically modified (GM) crops are those that have been genetically enhanced using modern biotechnology to carry one or more beneficial new traits. Modern biotechnology as defined by the Cartagena Protocol on Biosafety means the application of:
a. In vitro nucleic acid techniques, including recombinant deoxyribonucleic acid (DNA) and direct injection of nucleic acid into cells or organelles, or
b. Fusion of cells beyond the taxonomic family,
that overcome natural physiological reproductive or recombination barriers and that are not techniques used in traditional breeding and selection
The first GM crop developed through the use of transgenic methods and approved for cultivation was the ‘Flavr Savr’ tomato in 1994 in the US. Since then the development of transgenic crops has been rapid, from less than 5 million ha cultivated globally in 1996 to around 59 million ha in 2002 (See the annual publication by Clive James for the global status of commercialized transgenic crops for the latest figures). The main commercially released crops so far have traits of agronomic interest, the so-called ‘input’ traits, such as herbicide and insect resistance. In the short to medium term, transgenesis will be used to transfer the so-called ‘output’ traits in crops such as: nutritional content e.g., higher vitamin content in soybean, oilseed rape and rice; and higher iron content in rice
nutritional profile e.g., improved amino acid composition of maize, improved fatty acid composition of maize, soybean and oilseed rape
improved processing e.g., through modified starch in maize and potato, higher solid content in potato and improved fibre quality of cotton
reduction of post-harvest losses e.g., through delayed ripening in papaya and improved storage capacity of potato
The benefits and risks of GM crops are assessed by comparing the new crop and/or associated technologies (pest management or food processing) to its ‘conventional’ counterpart. Input traits in general lower the use of pesticides and as a consequence, benefit the environment and improve farmer revenues. More specifically, insect resistant varieties limit post-harvest losses (insect damage cause up to 50% loss of the harvested product in developing countries) and production of mycotoxins (the source of serious health problems), and herbicide tolerant varieties reduce soil erosion. Output traits will be of considerable benefit to consumers through access to healthier food.
The development of GM crops has benefited farmers, consumers and the environment. In a recent analysis of the total benefits to US society from Bt maize, when 6.5 million ha of a total of 32 million ha was planted by Bt maize, Wu (2003) showed that the major beneficiaries are consumers (63% of the total gains equalling USD 848 million). Maize growers are the second largest beneficiaries (22%) followed by the seed industry (15%). Non-Bt maize farmers made a net loss of USD 416 million.
Today, data shows that GM crops and foods are as safe as their conventional counterparts: millions of hectares worldwide have been cultivated with GM crops and billions of people have eaten GM foods without any documented harmful effect on human health or the environment.
Nevertheless, ISF is aware that as with any new product GM crops may be associated with some risks. These risks must be evaluated on a case-by-case basis. For instance the use of herbicide tolerance genes could result in the evolution of ‘super weeds’ resistant to herbicides*, or the introduction of allergens in the novel food through the transfer of genes from a species known to be allergenic. Some aspects are not specific to GM crops such as insects developing resistances to Bt genes. All these risks are taken seriously into consideration during the pre-release risk analysis and, where needed, specific risk management procedures may be established to prevent hazardous products being put on the market.
* The situation, if it were to occur, is not as dire it is seems. It is not dissimilar to the circumstances prevailing before the development of the herbicide tolerant variety.
Reference: Wu, F. 2003. Explaining consumer resistance to genetically modified corn: An analysis of the distribution of benefits and risks. Risk Analysis, Best Paper Issue (in press).
What is the Meaning of "Adventitious Presence" ?
Adventitious presence means accidental, unintentional presence. It is commonly used to characterize seed lots, e.g. adventitious presence in a seed lot of “off-types” not conforming to the description of the variety.A low level of adventitious presence of off-types is unavoidable in biological processes such as seed production. In national and international seed regulations, there are recognized standards for the level of adventitious presence of off-types. These standards are typically based on visual assessment of the seed production field and the resulting seed lot.
Adventitious Presence of Genetically Modified (GM) Material in Non-GM Products
The adventitious presence of GM material is the unintended occurrence of plant material from crops improved through modern biotechnology in other seed, food and feed. It occurs through natural pollen flow or from co-mingling of grain that occurs in the production/distribution system. It is the logical and unavoidable consequence of the development of GM crops in many parts of the world. In contrast to off-types mentioned in the previous section, which are checked on phenotypic characteristics, adventitious presence of GM material are in general checked based on DNA characteristics.
GM material that is found as adventitious presence in non-GM products is of three types:
GM material that is domestically approved
GM material that is not domestically approved but has been approved in another country that employs the OECD safety assessment process
GM material that is still at the research stage and has received approval for field-tests in any country member of the OECD Seed Schemes
Approval may be for different uses - cultivation, feed or food. Adventitious presence of GM material in categories 1 and 2 are more likely to occur. GM material in category 3 in non-GM products is less likely to occur but nevertheless requires consideration. In countries where labeling of GM products is required, accepted standards for the level of adventitious presence of GM material in non-GM products is necessary so as to:
review the quality assurance practices for seed production and, if necessary, to design new quality assurance processes that minimize adventitious presence through pollen flow and co-mingling
establish and optimize laboratory standards for assessing the presence of GM material in non-GM products
establish appropriate regulatory clearance procedures under OECD (or other international agencies) for safety assessment if GM material under consideration has not been approved in country of import
determine the market need for and cost to produce seed material with a specific tolerance for GM material
determine a workable standard below which products don’t need to be labeled, if at all, keeping in view its impact on cost of goods and market demand
What are "Genetic Use Restriction Technologies (GURTs)" ?
In nature, the expression of genes is regulated by several factors, which may be internal to the organism (e.g. proteins or other molecules resulting from the metabolism of the organism itself) or external (e.g. climatic factors).
Conventional plant breeding is aimed at introducing and recombining genes in order to improve crop performance. Modern biotechnology offers new tools (recombinant DNA, molecular markers, etc.) that facilitate and speed up the plant breeding process. Some can be used to insert new genes or remove specific genes (e.g. those coding for toxic or allergenic compounds). Others can be used to regulate the expression of genes that are, for instance, not desirable at a certain stage of crop development.
Methods that regulate gene expression are called Genetic Use Restriction Technologies (GURTs). In a sense GURTs can be seen not as a new technology but as a ‘domestication’ of the regulation of gene expression, a mechanism that occurs naturally in any organism. Plant breeders have until now focused their activity on the introduction and recombination of genes. GURTs will allow them to work on the expression (or the non-expression) of genes at any given stage of crop development or any generation. Some potential applications of GURTs could be:
increased production of specific molecules
regulation of the expression of resistance genes so that resistance is expressed only when necessary
preventing the spread of unwanted plants created by cross-pollination between GM plants and non-GM ones, landraces or wild relatives
improved protection of intellectual property rights