Summary
Since Gregor Mendel came with the idea of genes in the 19th century, studies and technologies in biotechnology and molecular medicine have advanced significantly, producing various techniques for manipulating animal and plants genetic makeup. In the 20th century, the idea of recombinant-DNA technology emerged from genetic studies, which sought to improve the breeding and biotechnological production of food (Nielsen 37). Since then, scientists in molecular biology, biotechnology, genetics, and medicine have utilized recombinant-DNA technology to manipulate genes and produced the desired genotypic and phenotypic characteristics. The application of recombinant-DNA technology in food production is perhaps one of the most important yet controversial uses of the technology. It involves the manipulation of plant and animal genes through the introduction of foreign genes into the target organism (or silencing a wild-type gene) to confer the required characteristics (Nielsen 38). The resulting organism, in which the native genes have been changed significantly due to the presence of foreign genes or silencing of the target gene, is popularly known as genetically modified organisms. In food production, genetically modified plants or animals are known as genetically modified foods. Over the years, a huge number of genetically modified plants have emerged from various laboratories across the world.
In particular, there is a wide volume of evidence supporting the effectiveness of these organisms to increase food production through resistance to pests, diseases, drought, increase in growth rate and quality as well as quantity of production. Nevertheless, a strong debate has emerged over the safety of these organisms, especially plants, in agriculture, the environment, and human/animal health. An important point of debate has resulted from the observation, or hypothesis, that genetically modified plants have the capacity to pass the modified DNA (and thus the genes of interest) into non-target plants, giving them the capacity to express the expected characteristics. For instance, a major scientific argument shows that most plants of the grass family, including corn, wheat, barley, rice, and others, have the capacity to exchange pollen with other members of the grass family, including the non-target plants, weed, and others (Losey, Rayor and Carter 214). The possible result is likely to be an exchange of the modified genes, giving the non-target plants the capacity to proliferate. Thus, it is possible to pass the genes coding for the resistance to a pest, diseases, herbicides, and drought or those coding for enhanced growth to these plants. This is a potential risk to biodiversity and the environment in general. In addition, the debate shows that gene modification in plants is likely to promote genes coding for other non-target genes, including the production of prolamines in rice, which causes allergic response among the consumers. Other effects are emerging as the technology gains use in various animals and plants.
Despite the large volume of knowledge in molecular and phenotypic aspects of recombinant-DNA technology, the impact of the modified organisms on the environment, biodiversity, human and animal health remains controversial. It is evident that a gap exists in knowledge, especially in explaining the safety of the genetically modified organisms in terms of their impact on biodiversity, rate of production on a long-term basis, human and animal health. Although researchers are still carrying out studies to fill this gap, it is evident that the long-term effect of these organisms on human health remains unknown. In addition, much of the modern debate about the safety of GMOs is based on fallacies, especially perpetrated by the media, popular culture, and enthusiasts rather than from scientific evidence. Thus, this paper seeks to address the question of whether genetically modified plants meant for food production confer a threat to human health and the environment, using recent scientific studies rather than the fallacies and hypotheses that have dominated the debate.
Background
Recombinant DNA technology is the principle behind the development of genetically modified organisms and foods. The technology is based on the idea of transferring some specific gene or groups of genes through infection of DNA sequences from one organism to another, through a vector or advanced technique. In general, the gene of interest is obtained from the genome of an organism demonstrating the desired characteristic such as pest resistance. According to Muir and Howard (13854), DNA isolation from the cell requires advanced technology, but the major forms of transferring the genes from one organism to the other are transformation, non-bacterial transformation, transduction, and phage introduction. In brief, they involve inserting the desired gene sequence in a vector such as a bacteriophage (a virus that affects bacteria), a bacteria infecting cells, or technologies such as biolistics that allow DNA bound to tungsten particles to be bombarded into the target cells. Once inside the target cells, the DNA carrying the gene of interest is inserted into the host cell genome and expressed, given that expression factors such as promoters and proteins are supplied along with the gene of interest.
The resulting organism will have some of its expressed genes being foreign, which confers the desired characteristic. According to a study by Takeda and Matsouka (445), most of the research projects carried out between the 1980s and 2010 used food crops, including corn/maize, rice, tomatoes, potatoes, beans, peas, wheat, soybean, canola, and several types of fruit plants. This study reveals that the major purpose of most studies is to enhance and sustain food production. In fact, this supports a previous study by Takeda and Matsouka (449), which had shown that most of the characteristics that scientists are looking for in plants are those associated with resistance of food crops to harsh environments, diseases, pests, chemicals as well as the genes coding for increased ability to tolerate salts, boron, and other chemicals. A study by Domingo and Bordonaba (752) reveals that most projects in developing GMOs seek to ensure that plants grow and proliferate in areas that they would otherwise not grow due to environmental conditions. For example, Domingo and Bordonaba (752) report that gene Cry1 Ab from Bacillus thuringiensis codes for Cry1 Ab protein, which has a high potential to resist insects, especially the European corn borer. Thus, this gene has been obtained from the Bacillus and transmitted to corn, improving production due to pest resistance. According to Hashimoto (1611), genes are also exchanged between food crops, which improve their characteristic. For instance, a gene coding for glycinins in soyabean is extracted and transmitted to potatoes to improve the production of this compound in potatoes.
In addition, several studies have shown that a significant number of projects have led to improved animal breeding and enhanced their resistance to diseases. For instance, the researchers such as Hashimoto (247) at recombinant-DNA technology have been applied to transmit genes coding for resistance to mad cow disease in cattle, which has produced excellent results.
Justification
Although the short-term effects of the recombined genes in GMOs are already observable, it is worth noting that few studies have provided evidence of the possible long-term effects on human health. First, it is evident that most of the transformed plants with recombinant-DNA technology are food crops, which are meant for human consumption. It is clear that technology has enhanced food production, especially in a world faced with shortages of food due to environmental change and increasing population. According to Demont (48), there is a disparity in knowledge development because most researchers are driven by the desire to achieve the short-term benefits but fail to consider the possible health outcomes of feeding on these plants, especially after several years.
A study by Domingo (736) has attempted to review the number of studies examining the possible toxicity of genetically modified plants in the environment as well as on the consumers. However, the study found that a number of researchers fail to study the potential use of genetically modified plants meant for humans and animals. In addition, Domingo found that most of the published materials on the toxicity of some of these crops do not provide a report from biotechnology companies that produce the GMOs, which creates a major disparity in scientific evidence.
However, a study by Nicolia, Manzo, Verosi, and Rosellini (2013) has attempted to review the crop safety measures taken in genetic engineering since 2000. The study shows no evidence of possible safety concerns of most crops, including the foods that have been intensively used as food crops for humans as well as animal feeds.
Nevertheless, this finding does not necessarily mean that humans and animals are free from the negative impacts of feeding genetically modified foods. For instance, the recent case of Bt corn has revealed that some health aspects of the GMOs are ignored when developing them (Flachowsky, Halle, and Aurich 57). According to the studies by Losery (2009), the mortality of monarch larvae was found to be higher when the animal was fed with milkweed with pollen from genetically modified corn than when fed with milkweed covered with pollen from the wild type corn. An additional study by Jesse and Obrycki (2010) suggests that a large population of the monarchs died after feeding on natural levels of pollen from Bt corn in a field. Thus, this study confirmed the earlier reports that some aspects of GMO development are ignored, yet few studies are attempting to carry out health surveys on both animals and humans feeding on these organisms. Most of the claims that such institutions and agencies such as the FDA, FAO, WHO, and the American department of health make are based on studies on the short-term effects of genetically modified foods. They use the claims from empirical research to show that the impact of GMOs on human and animal health is little if any because most of the modified genes are obtained from other plants. Proponents of the technological application in food production claim that humans and animals consume more than 1.0g of foreign DNA in food every day, but the biochemical system has the potential to digest and break down the foreign DNA. This means that ingested genes have little impact on our health. Yet, some researchers have shown that foreign DNA can also stimulate the human immune system or promote the formation of bacterial biofilm (Rizzi 151). Thus, it is important to determine the health impact of transgenic consumption in foods.
From this analysis, it is clear that efforts, resources, and expertise are needed to increase the number of studies on the potential impact of GMOs on humans and animals. It is evident that the current claims that these foods have no health impact are not based on research because the recombinant DNA technology is relatively young. This means that the long-term effect of these foods is unknown. In addition, most researchers tend to concentrate on the potentials of these foods and ignore studies on their negative impacts.
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