The World Health Organization defines genetically modified organisms (GMOs) as organisms in which the genetic material (DNA) has been altered in a way that does not occur naturally.
The technology is called biotechnology or genetic engineering and it is involved in the production of foods called genetically modified foods or GM Foods. GM foods are foods produced from GMOs or organisms that have had specific changes in their DNA using the methods of genetic engineering or biotechnology. A number of organisms including micro-organisms such as bacteria and yeast, insects, plants, fish, and mammals have been genetically modified.
Genetic material of organisms consists of DNA or RNA that serves as the blue print dictating the physical characteristics of the organism or living thing. At the cellular level, and in some cases embryonic stage, many organisms, including microorganisms (e.g. bacteria, yeast and molds), mushrooms, plants, birds, insects, reptiles, fishes and mammals, are very much alike in their physical appearance or phenotypes.
However, the phenotypic differences become well pronounced once they grow. Growth which is directed by the instructional units or segments of DNA referred to as GENES bring about the phenotypic differences that exist among the various organisms. The degree of the genetic (or GENE) differences brings about categorization of all organisms on Earth into various Classes, Genera, Species, Varieties or Breeds or Strains. This order of genes and its consequent inheritance is what is cleverly described in the local parlance as “okoto nowo anoma” (literally translated as ‘a crab does not produce a bird’).
How are GMOs produced?
Genetic engineering was first performed by Prof Paul Berg and immediately followed by the works of Herbert Boyer and Stanley Cohen in the 1970s. Thanks to the contribution of a number of renowned scientists to the development of biotechnology.
Significant among them include James Watson and Francis Crick who first elucidated the double helix structure of DNA in 1960s. This was followed by the works of Alan Maxam and Walter Gilbert (1976-1977) and Frederick Sanger (1977) who introduced techniques for sequencing or decoding DNA into the four basic building blocks called nucleotides (i.e., A, T, G, and C).
With the current advancement of genetic engineering where entire genomes or DNA of organisms including humans, important crops and domestic animals, have been sequenced or decoded, scientists have succeeded in identifying, isolating, and modifying GENES that control specific traits or phenotypes.
For example, some genes are known to control growth, formation of insulin and other essential proteins. Some control production of vitamin A and other nutrients, and others confer resistance to insect, herbicide, fungi, drought and viral attacks in plants.
In principle, any gene could be removed, altered and transferred back into the organism or into another that is either sexually compatible or incompatible with the donor organism. What is unique about biotechnology in contrast to traditional breeding is its power to transfer genes between organisms that are sexually unrelated. Thus, one could obtain a desirable gene from fish, say a gene that makes omega-3 fatty acid found in cooking oils good for combating heart diseases, and transferred into soybean plant for the purpose of commercial production of premium soybean oil.
Does traditional breeding involve alteration of genes or DNA as in biotechnology?
Traditional or conventional breeding also involves changing the genes of an organism (plant or animal) so that a new and better variety or breed is developed. Unlike genetic engineering, traditional breeding usually involves two closely related plants or animals that are sexually compatible and capable of crossing (by pollination or mating) to yield an offspring or young one. The progeny of this first cross inherit a mix of genes from both parents and so both positive and negative traits may be inherited. A series of backcrossing spanning several years, sometimes a lifetime of the farmer, are performed until the progeny have all the desirable traits and none of the negative ones of the original two parents. Occasionally, traditional plant breeding may use ‘wider crosses’ that involve crossing species or even genera that are quite unrelated. These crosses cannot occur without help – so sophisticated techniques are employed.
What are the benefits of GM foods?
With an ever increasing global population, sporadic third world hunger, and with an estimation that a child dies every two seconds worldwide from starvation, aside the millions of people who are malnourished and/or undernourished, there is a great promise in the use of biotechnology to sustainably meet the worldwide demand for abundant and quality food supply. Some benefits of the GM foods include creating plants with better resistance to weeds, drought, pest and diseases (insect, fungal, bacterial or viral), e.g. Bt corn; higher yields of crops to create more efficient use of land, less uses of herbicides and other pesticides; foods with better texture, flavor and nutritional value; and foods with longer shelf life for easier shipping. GM foods were first commercialized in the United States in 1994 when the first GM tomato Flavr Savr was produced for its longer shelf life property. This was followed by introduction of GM cereal crops in 1996. Today a number of GM crops have received licenses for commercial production.
Can I identify GM foods on the market?
Unfortunately, until 2011 when Ghana Parliament passed the Ghana Bio-safety Act 831, no rigorous procedures were in place to screen foods imported into the country for genetic alterations or GM. It is hoped that the Ghana Biosafety Authority, once established physically, will supervise such screening exercises. Countries in European Union require that foods containing GM are labeled. Some European countries have established permissive GM levels in some foods imported. However, the United States government does not require labeling of GM foods. Thus, labeling of GM foods in the States is not mandatory. Some companies, however, label their GM foods voluntarily. Research shows that nearly 80% of foods in countries such as the Americas and Asia involved in GM food production are contaminated with GM foods. It is therefore tempting to conclude that since a sizeable percentage of our imported foods, especially cereal products, vegetables and cooking oils, come from these countries, Ghana is already exposed to GM foods. However, this deduction could only be ascertained by a market survey based on marker-assisted molecular screening at entry points and across the country.
What are some of the risks associated with GM Foods?
Elsewhere, every plant improved through the use of food biotechnology is examined by the FDA and EPA for potential health risks. Tests are done on plants before entering the food and animal feed supply. The World Health Organization (WHO) reports that current foods containing biotech ingredients have passed human health risk assessments. In addition, the WHO says no effects on human health have been shown as a result of the consumption of biotech or GM foods.
However, a number of concerns were raised at the early stages of commercial introduction of the two-decade old technology, especially in the 1990s and early 2000s. Critics cited a number of issues concerning legal risks, risk to humans, environmental risks, and ethical and religious concerns. A complete understanding of risk must also include the benefits that accompany those risks.
Often, when one considers the potential for GM Foods to present a hazard, examples of plants that have been introduced with negative unintended results are desirable. Although several introduced plants have caused negative environmental impacts, such as water hyacinth, numerous other introduced plants have made tremendous positive impacts.
For example, maize, potato, tomato, cassava, rice, wheat and soybeans are not native to many countries yet they form the foundation of these countries’ agriculture today. In the strictest sense, any genetic changes occurring via traditional breeding or by genetic engineering will have some measurable impact on the environment.
Are there health risks associated with GM Foods?
The World Health Organization (WHO) has stated that no effects on human health have been shown as a result of consumption of GM foods across the world. Perhaps the greatest concern over the release of transgenic plants into the environment is the potential for new sources of toxins or allergens in the food supply. A number of studies carried out on the health implication of the consumption and application of GM foods failed to establish differences between GM and non-GM foods.
However, some studies have found that allergenic properties associated with some genes have been produced in GM foods, demonstrating that an allergenic factor from one plant species can be transferred into another by genetic engineering. However, it has long been known that allergenic properties of related plant species tend to be similar; suggesting that sources of genes for plant improvement may be guided by knowledge of related species to ameliorate the possibility of creating a new allergenic plant type.
Nonetheless, a great deal of concern has been expressed by the public over the presence of transgenic plant materials in food products. The finding of any transgenic plant material not approved for human consumption in food products will definitely cause a great public outcry, a situation currently observed in Ghana.
Are there some legal risks involved in the introduction of GMOs?
Many possible legal issues surround GMOs and have already started to affect society on personal, national and worldwide levels. Recently, it has been established that pollen dispersal distances can be several kilometers.
Thus the earlier small-scale studies carried out to predict pollen movement underestimated the possible distances. Hence, the risk of contamination of non-transgenic crops with transgenic pollen can be very great. It is apparent from recent legal rulings in other countries that growers of transgenic crops such as maize who do not report genetic contamination to the company owning the patent on a gene may be sued for patent infringement even if they gain no economic benefit from the unwanted gene flow into their fields.
Uncontrolled gene flow via pollen or seeds raises many legal issues. It is possible that growers may lose the right to save the seeds from their own landraces or varieties that they have developed, possibly after many years of selection, if those populations are contaminated with patented genes. Should growers be obliged to adjust their crop rotation, herbicide schedules, and field layout in order to protect their crops from contamination from neighboring transgenics?
Should growers of non-transgenic crops bear the cost of dealing with gene flow that is unwanted and arguably forced upon them? Will companies or nearby growers reimburse non-GM growers if gene flow forces the non-transgenic grower to use a more costly herbicide or less efficient crop rotation plan? Contamination of fields with engineered genes may prevent products from being marketed as “GMO free” or “organic.” Who will reimburse losses of growers targeting these premium-price markets? If a consumer or company claims to be injured by the use, production, or transportation of GM crops, can growers be held liable?
It is possible that the widespread use of transgenic crop varieties will lead to the loss of markets for farmers producing the transgenic products, regardless of the legality of those crops.
For example, widespread public disapproval of transgenic crops in Europe essentially removes the European market as an outlet for transgenic crops grown in the United States or elsewhere, even though no legal bans might have been in place in such countries. In this situation, a farmer attempting to grow non-transgenic crops may lose access to a market if his or her crop were to become contaminated with transgenic pollen. These and many other issues clearly constitute a set of new risks that consumers, growers, and companies continue to face.
Are there some environmental risks posed by the introduction of GMOs?
Considerable discussions have ensued concerning the impact transgenic crops may have on surrounding plant and animal populations. Perhaps the two most widely discussed cases to date are those of possible contamination of wild populations of maize in Mexico with transgenic pollen, and the possible killing of monarch butterfly larvae by maize pollen expressing Bt toxin incidentally deposited on milkweed plants. Earlier report indicated that Bt maize pollen could cause significant death of monarch butterfly larvae feeding on milkweed plants in and around transgenic maize fields.
However, this conclusion was challenged and led to a spate of investigations and reports which indicated that the impact of Bt maize on the monarch butterfly was negligible. Nonetheless, the potential for the kind of impact reported in this case cannot be ignored and should be investigated for any new transgenic crops prior to their approval and release.
Another potential environmental risk of GM crops is the loss of native or wild-type varieties through hybridization with the cultivated GM crops when introduced into the natural habitats or ecological zones harboring the wild plants.
There may be unexpected benefits to growing transgenic crop plants. The Green Revolution was made possible largely by the introduction of a very few genes.
Even though Green Revolution varieties greatly increased crop yields in much of the developing word, these varieties also required intensive fertilizer and pesticide inputs. In the 1980s, many environmentalists began to oppose the use of high amounts of inputs because of environmental pollution.
However, those environmentalists overlooked a major environmental benefit of the Green Revolution, a tremendous worldwide drop in deforestation.
In fact without high-yield agriculture, either millions would have starved or increases in food output would have been realized through drastic expansion of acres under cultivation – losses of pristine land a hundred times greater than all losses to urban and suburban expansion. It has been estimated that in India alone, natural wilderness equal to ten times the size of Ghana would have been lost to cultivation if not for the Green Revolution. One or a few transgenes of the future may have similar, unexpected benefits.
[Written by: Dr. Peter Twumasi, Senior Lecturer, Department of Biochemistry and Biotechnology, KNUST; President, Ghana Science Association, Kumasi Branch.
The author holds MSc and PhD degrees in the area of Microbial and Plant Biotechnology from Wageningen University and Research Centre, The Netherlands.]