Genetically engineered organisms and agriculture

In countries such as the USA, Argentina and Brazil, genetically engineered crops are already grown for food on millions of hectares of land. In addition, genetically engineered salmon and transgenic flies have been developed and may soon be on the markets.

The difference between conventional breeding and genetic engineering

Conventional breeding works with the whole cell and the complete genome of plants and animals. Genetic engineering on the other hand, works with isolated parts of DNA, which are used as building blocks to construct organisms with new characteristics. The biological activity of the newly inserted DNA is enforced through technical means, thus bypassing the cell’s own gene regulation and the natural mechanisms of heredity. Genetic engineering is different to methods used in conventional breeding because it aims to enforce new metabolic pathways in the plants. Conventional breeding uses the natural potential of the plants originating from evolutionary pathways. Even mutation breeding is based on the mechanisms of evolution: In this method plants are, for example, constantly exposed to stress factors (such as UV-light) to bring about mutations. There are constant changes in the genomes of plants, but it is natural cell regulation which will determine which mutations finally prevail. Thus, organisms derived from the process of genetic engineering can be regarded as substantially different when compared to those derived from conventional breeding or those which have evolved naturally.
Understanding the difference between conventional breeding and genetic engineering is important when it comes to risk assessment for human health, the assessment of gene flow into ecosystems and the gene pool of native populations or other crop plants. The changes to the gene function and metabolism enforced by genetic engineering often impact the activity of other genes in the plants. Such unintentional side effects can affect the genome, the cell or even the whole organism. Genetic engineering may force plants to produce new proteins (such as insecticidal proteins) based on metabolic pathways that would not occur through mutagenesis. Plants are not able to adapt naturally to these pathways through evolutionary processes and, consequently, there may be other undesired effects in the plants, such as changed composition or a higher potential to persist and invade the environment. This in turn means that there may be substantial risks for humans and the environment, which need to be taken into account.
The differences between conventional breeding and genetic engineering may have many other ramifications. More complex genetic traits - such as gene function contributing to higher yield or resistance to environmental stressors (such as climate change) - might be difficult or even impossible to achieve. In this context, conventional breeding methods are often more successful. There are good reasons for this: In many cases, preferable traits are not based on single DNA sequences, but on complex genetic interactions. These can often be achieved much more effectively by using the plant as a biological system in conventional breeding, rather than by inserting sequences of isolated DNA like single building blocks.

Who benefits?

Seeds developed through genetic engineering are almost exclusively offered by agrochemical companies: Monsanto, Dupont, Syngenta, Bayer and Dow Chemical are the big players in the international seed industry. These corporations buy up seed companies, file patents on DNA, plants and seeds and use patents to claim the whole chain of food production right up the consumer. Business with genetically engineered plants is mainly focused on five countries, the United States, Brazil, Argentina and Canada, which mainly grow crops for animal feed (soybean and maize) and some cotton, and India where GE cotton is grown extensively. Almost all GE plants have either been made resistant (or tolerant) to herbicides or they produce insecticidal proteins. There are currently an increasing number of combinations of these traits in so-called stacked events.
Genetically engineered plants may ostensibly offer benefits to farmers who want to save time spent on weed control in their fields. And, if pressure from specific pest insects is particularly high in some years, insecticidal plants may render higher yields. However, the genetically engineered plants currently on the market do not render higher yields per se. Moreover, not only do the weeds become increasingly resistant to herbicides such as glyphosate, the pest insects also adapt to the cultivation of genetically engineered plants. Evolutionary processes are, in fact, negating the traits developed by the biotech companies. As a result, both the usage of pesticides and the farmers’ workload are increasing.
The contamination of the food chain with genetically engineered material is yet another problem that needs to be dealt with. Contamination can start with the seeds, and later on at the cultivation or food processing stage may cause serious economic damage. Although several genetically engineered plants have been approved for import into the EU for use in food and feed, the cultivation of genetically engineered plants is highly restricted. To date only very few genetically engineered plants have approval for cultivation.