The development of genetic engineering (GM) technology makes it possible to overcome two limitations: one, the length of time needed to insert the desired gene and the second - loss of desired genes on the one hand and introduction of negative genes on the other.
Rebecca Berg and Jacob Berg
Galileo - from issue 83 of July 2005
The editor of the scientist comments: This article was written following a series that began with my article (Galileo 60) and an article counter to my articles published in issue no. 63. In the meantime, another article of mine on this topic appeared in Issue 84 (August 2005) following a discussion on this topic in the Knesset. The articles themselves are in the link below.
Transgenic plants: chances, risks and the legislation in between
In issues 60 and 63 we discussed the reasons for and against the use of genetically modified plants. Here is an extensive and updated article on this topic, which also includes an overview of the positions of different countries in the world in relation to this issue. The position currently accepted by most experts is that, although the possible risks of widespread use of genetically modified plants cannot yet be ruled out, it is most likely that no immediate and significant danger arises from them, or from food derived from them. The rate of change in the world's seed areas overshadows the whole discussion
Gene - a segment of DNA that contains information about a certain hereditary trait, usually - information for the production of a certain protein.
Genome - the total hereditary material characteristic of the biological species, in most biological species is made up of DNA units.
Genetic engineering - a variety of molecular technologies that make it possible to transfer a gene originating from any biological species, or produced in vitro, to another species, thereby permanently changing the genetic characteristics of the genetically modified species.
Transgene - a foreign gene integrated into the genome of an organism (creature) using methods of genetic engineering.
Transgenic plant (transgenic plant) - a plant to whose genome foreign hereditary material (transgene) has been added through methods of genetic engineering.
Genetically Modified, GM - genetic modification of creatures through methods of genetic engineering.
Canola - commercial name for the rapeseed plant from the cruciferous family, which was cultivated years ago using accepted cultivation methods, for the production of edible oil. The oil from the uncultivated plant is not edible.
Mitochondrion - ATP production organelle.
Chloroplast - the carbon dioxide assimilation organelle in plants.
Since the dawn of agricultural culture, for thousands of years, man has been breeding plants from wild plants, with the aim of obtaining varieties that farmers grow for the welfare of mankind. The variety of genes in each biological species is the factor that limits the possibilities of classical cultivation. When a new plant disease appears that attacks several species, finding a plant resistant to the disease among the wild relatives of a certain species allows the integration of the gene that confers resistance in the cultivated varieties by hybrids between the resistant wild plant and cultivated varieties of the same species; But because of the natural barrier to intersexual hybridization, the same plant cannot be used as a source of imparting resistance to other species attacked by the same pest or disease agent. Furthermore, the classic process of hybridizing plants and cultivating them to incorporate new genes into advanced agricultural varieties is very lengthy and requires a lot of effort. The initial hybrid between the cultivated variety and the nearest wild species does contain the necessary gene but also contains many genes that carry negative traits. During hybridization, some of the positive traits of the culture strain are also lost. In the conventional technique, the negative traits are eliminated in a long series of hybridizations and the desirable traits of the cultivar are restored. Sometimes it is not possible to fully restore the desired traits that have been worked for years to integrate into the cultivars.
The development of genetic engineering (GM) technology makes it possible to overcome two limitations: one, the length of time needed to insert the desired gene and the second - loss of desired genes on the one hand and introduction of negative genes on the other. This technology allows the insertion of a single gene, originating from any organism, into the cultivated plant. Thus, the variety of sources from which it is possible to "borrow" the gene responsible for the trait that one wants to integrate extends to the entire animal world, and in addition it is possible to build new artificial genes that do not exist in nature (for example, by deliberately changing existing genes). Genetic engineering also includes a variety of technologies that make it possible to integrate the desired gene "in one fell swoop" - and not through sexual hybridization - in the cultivated species, without harming the rest of the desired traits, thus shortening and optimizing the cultivation process.
This technology, which makes it possible to "engineer" cultivated plants, carries with it enormous possibilities for improving the quality of life, and already today its application considerably increases food production. Since the technology is powerful and is based on breaking the barriers that exist in nature to prevent the transfer of genes between different species, its application outside the laboratory provokes a fierce public controversy and opposition mainly due to two reasons:
A. A religious concept that sees genetic engineering as an intervention in the act of creation.
B. Fear of future risks, even those currently unrecognized, which may increase with the widespread use of technology.
The concerns about the future risks refer to both the effect of the engineered product on the consumer and its effect on the plant and animal environment. So far, the fears about the future risks have not materialized.
The advantages arising from the genetically modified plants on the one hand, and the concerns regarding their use on the other hand, require creative and in-depth thinking by organizations from the field of agriculture, science, industry, law and consumers. This multidisciplinary approach creates a dialogue from which procedures and legislation are derived. In this article we will explain the main points of the technology, its advantages, possible risks, technologies developed to deal with the risks, and review the legal status of the production and cultivation of transgenic plants in Israel and in some countries of the world.
The accepted technologies for creating transgenic plants
In all living organisms, with the exception of some viruses, each gene that dictates a hereditary trait is a segment of the DNA molecules that constitute the entire hereditary material (genome) of the biological species. Changing the hereditary material through genetic engineering includes three stages:
1. Identifying and isolating a gene (DNA segment) from some organism that controls the feature that you want to incorporate into the target plant. Alternatively, an artificial garden can be built in a test tube that will control a desired feature of the transgenic plant.
2. Development of technology for transplanting the foreign gene into the genome of a cell of the target plant.
3. Development of technology to create a complete and fertile plant from the cell into which the foreign gene was inserted.
The two most common technologies for transplanting a transgene into the plant cell ([PIC1]):
A. The "biological" method that combines physical and biological technology. With this method, a large amount of transgene copies are created which are coated on tiny spheres of metal (gold or tungsten). The pellets coated with the gene are shot using a "gene gun" into plant tissue. In a small number of the "bombed" cells, some of the globules penetrate the cell nucleus, which contains the hereditary material, and the foreign gene is physically integrated into the cell's DNA.
B. Transformation using a genetically modified Agrobacterium bacterium. Originally, the bacterium causes disease in many plant species and is a parasite which, during evolution, developed a sophisticated mechanism to transfer some of its genes to the genome of the plant cells, which serves as a "host" on which the bacterium feeds. Using genetic engineering methods, they changed the bacterium so that it is still able to transfer DNA segments to plants, but without causing disease. The transgene that they wish to transfer to the target plant is incorporated into the "carrier" molecule of the transgenic bacterium. Infection of plant tissue with the engineered bacteria leads to the transfer of the DNA segment integrated in the carrier into the plant's genome (the use of this bacteria is most acceptable in the genetic engineering of plants, while other carriers are used in animals). Later, the transduced cells undergo multiplication and selection and a transgenic plant is created from the transduced cells. In the genetic engineering technique, there must be a stage of creating a complete plant in vitro from the transgenic cells. After the creation of the plant, it can be propagated sexually (by seeds), or asexually.
The public is not afraid of the very technologies for introducing the transgene; However, there are those who fear the transgenic plants themselves. Asexual propagation of the transplanted plants is also not a problem since the traditional means of plant propagation do not cause concern in the public's heart. Since the dawn of agriculture, man has propagated plants asexually, such as fruit trees from cuttings, bananas from cuttings, onions, garlic and potatoes from bulbs and tubers. Regarding plants, this technology is accepted as "safe", in contrast to the vigorous opposition to the cloning of animals and humans, an opposition that increased with the success of the cloning of the sheep "Dolly". Regarding cloning, a legislative effort has been made in many countries in the world, including Israel, with the aim of prohibiting genetic intervention and human cloning.
About the authors
Dr. Rivka Berg, Senior Researcher, Department of Genetics, Field and Garden Crops Institute, Valkeni Institute, Director of Agricultural Research. Prof. Jacob Berg, Associate Professor, Fellow in the Faculty of Agricultural, Food and Environmental Sciences, Institute of Biochemistry, Food and Nutrition Sciences, School of Food Sciences, Hebrew University, and the Department of Criminology, Ashkelon Academic College.
