If you could prevent a lifetime of blindness with rice, would you?
GENETICALLY ENGINEERED FOOD:
FOR AND AGAINST
Päivi Järvinen, Kaisa Karhumaa & Suvi Rönkönharju
Very little of what we eat can be described as natural. For example tomato was a small toxic South American berry before its domestication and the kiwi fruit was first a tiny, bitter gooseberry. This change has been achieved by traditional breeding. Genetic modification is really nothing new, it could be only considered as selective breeding and hybridization. The use of genetic engineering is much faster than traditional methods and genes can also be transferred from one species to another.
Different kinds of traits can be improved by genetic engineering, like pesticide, insect and disease resistence, higher yields, additional vitamins and nutritional qualities. Some varieties are already commercially available in USA including corn, soybean, canola, tomato, squash, potato and cotton. About 60% of all processed food in North America, for example candy, syrup, salad dressing and chocolate already contain GMO ingredients. In Europe public concern has prevented commercialization of genetically engineered products almost totally.
This new technique has received an enormous amount of criticism. Many environmental and consumer right groups fear unexpected consequences to the environment and human health. Some groups have even destroyed field trials. Also, some supermarket chains have decided not to sell GM-food.
We have tried to find out what this gene manipulated food is all about, what are the benefits and concerns, and why it is dividing opinions so strongly.
Ecological benefits and threats
Health issues
Ethical issues
Bt-maize
Golden rice
Terminator technology
Ecological benefits and threats
Ecological affects are perhaps the most important issue concerning GM food. There is concern about transferred genes spreading out to nature through pollination. For example, genetically modified rape has been shown to have transferred its herbicide resistance to nearby wild brassicas, creating superweeds. On the other hand, genetically modified crops usually don't have close wild relatives and for example maize, rice and wheat don't cross with related species. Genetic modification is also feared to reduce variation in crop species.
Pests can evolve resistance towards toxin produced by the GM plants which could lead to more problems. This has happened for example with bt-modified maize. Some genetically modified crops may also be harmful to beneficial insects. In addition, Greenpeace claims that genes may also spread to micro-organisms living in soil or water, creating new varieties with undesirable results.
According to biotechnology company Monsanto, genetic engineering offers many environmental benefits. It can reduce the need for pesticides, water usage, soil erosion and greenhouse gas emissions by more sustainable farming practices and more effective use of cropland.
Health issues
GM food is extensively tested, and it's safety is well proven. However, many people don’t want to eat GM food because they are worried about their health.
A common fear is that transferred genes might cause allergic reactions and create new allergies. In addition, consumers may not be aware that the transferred gene might be from an organism they are allergic to. For example, in a study of University of Nebraska, soya beans genetically modified to contain brazil nut proteins caused reactions in individuals allergic to brazil nuts.
According to biotechnology companies the use of biotechnology allows elimination of allergens, reduction of undesirable qualities such as content of saturated fats in foodstuffs, and also increase in beneficial nutrients, for example vitamin A. Because of the need for less pesticides and hebicides in farming, food products contain less harmful chemicals.
One of the most extreme opinions is Greenpeace claiming that antibiotic resistance genes used in genetic engineering can be transferred to bacteria on the digestive tract of humans.
Ethical issues
Some people think that genetic modification altogether is unethical. Still, using genetic engineering is more easily accepted in medicine production than in producing GM food. Sometimes strong opposing of genetic modification is due to lack of knowledge. This is partly because controversial information from scientists and media.
One ethical benefit of genetic modification of crop plants could be helping developing countries by making higher yielding and more nutritious crops. On the other hand, this could make farmers dependent on biotechnology companies. Because of the sterile seeds of GM crop plants the farmers have to buy new ones every year.
Because of strict legislation concerning GM food in Western Europe, many countries in Eastern Europe and developing countries are afraid that biotechnology companies may take advantage of them.
Because part of consumers refuse to eat GM food at all, the products should be labeled properly. All the consumers should have their right to decide whether to eat GM food or not.
BT-MAIZE
One of the most discussed genetically modified crop plants is Bt-maize, which contains a gene from a soil bacterium Bacillus thuringiensis. The transferred gene codes for protein Cry IA(b), which is a toxin that makes the plants resistant to certain pest insects. The toxin is very specific and it is harmful only to European corn borer and the spruce budworm. It affects the digestive system of these insects.
The use of Bt-toxin reduces the need of organophosphate insecticides, which are much less spesific and kill insects indiscriminately. Bt-toxin has been used as a spray for 40 years, but incorporating the gene to crop plants makes the plants protect themselves. Using this toxin as a spray protects the plant only outside the plant. If the corn borer burrows into the plant, spraying is ineffective. Transgenic Bt-toxin is expressed throughout the plant, which makes it a more effective way to use this toxin.
The Bt-toxin and the genetic material necessary to its production are proved to be safe to humans, including infants and children. Bt-toxin is commonly used in GM-plants produced and eaten in USA, and no health effects have been found. Bt-toxin is also known to break down to harmless substances in the soil.
One problem in the use of Bt-toxin is that insects have been shown to be able to create a resistance against this toxin. For example a vegetable pest Plutella xylostella (diamondback moth) has become resistant to Bt-toxin, but after using this toxin as an insecticidal spray, not as a transgene. Resistance due to transgenic Bt-cotton has also been documented. Insects becoming resistant can also happen using any other toxin or traditional chemical insecticides, and is perhaps impossible to completely avoid.
A study of Cornell University concerning Bt-toxin and Monarch butterflies has caught a lot of attention. Monarch butterflie larvae feeding on milkweed leaves dusted with pollen of Bt-maize grew more slowly or died. This was a laboratory experiment, and criticists claim that in nature such a large amounts of pollen on milkweed leaves are unlikely more than a few feet from flowering maize. Also, remains of chemical pesticides on milkweed would not be that healthy to butterflies either. Whatever the case, the study has raised a lot of discussion about genetic modification of crop plants.
GOLDEN RICE
Golden rice is gene engineered rice, which is hoped to help people suffering from vitamin A deficiency. The lack of vitamin A causes total blindness and night blindness, and affects about 400 million people mostly in Asia and Africa.
The normal rice doesn’t contain vitamin A or it’s precursore beta carotene. However, the Swiss scientists managed to transfer four enzymes to rice, and they altogether act and get one of the rice molecules to be converted into beta-carotene. Two of the enzymes were cloned from daffodils and two of them from a bacterium. Transformation of the gene was easily detected, because beta carotene gene changed the colour of rice grain to golden.
Furthermore, this same rice could overcome iron deficiency as well. Rice normally contains a molecule called phytate that ties up to 95 percent of the iron a person consumes. Three new genes should be transferred, one gene codes for an enzyme called phytase, which breaks down the phytate. A second gene codes for an iron-storage protein that doubles the iron level in the rice grains. The third gene provides a sulfur-rich protein to help the human digestive system absorb the iron.
This beta carotene rice and iron enriching rice could be hybridized to create one "super-set" of plants, and it could be used to treat both vitamin A and iron deficiences. This could help millions of people who are affected by these deficiences.
No doubt that a lot of people have been excited about these news. It has already been promised that the rice grains will be given to poor countries for free, and these kind of discoveries should give more positive image of genetic engineered organisms in overall.
Still there are a lot of people and organizations against the "Golden Rice". Greenpeace for example claims that genetically engineered rice is not going to win VAD (vitamin A deficiency), instead might even get it worse. According to Greenpeace hunger and malnutrition isn’t due to the gap between the human population and the food production, but to the poverty and lack of access to food, which "Golden Rice" wouldn’t address. They are also concerned that diet would be based only on the "Golden Rice", instead of the re-introduction of various vitamin rich food plants, which would prevent people from wide variety of micronutriet deficiences.
Besides Greenpeace claims that people who suffer from malnutrition couldn’t be able to absorb the beta carotene, because the absorbtion needs a variety of factors for example the presence of fats (the request that famished person doens’t necessarily fill). "Golden Rice" might be available for local planting 2004, but Greenpeace doesn’t think that’s enough time to study local socio-economics, health and environmental impacts. They also believe that the "Golden Rice" has a strong commercial base, and it’s unethical to make farmers dependent on the company by selling the seeds that can only be used for one year.
One of the funniest claims that Greenpeace has proposed is that "Golden Rice" should be banned because it would increase the unequality between the rich and the poor. The rich would still be eating the white rice and the poor would have to eat the yellow rice.
Even the developers know that there are still lot to study about, the field experiments etc (the first news about "Golden Rice" has been published in August 1999). Still the new technology should be given an opportunity, because it clearly has a good purpose.
TERMINATOR TECHNOLOGY
Terminator technolygy is a biotech discovery that can render seed sterile. This "technology protection system" is developed by USDA (U.S. Department of Agriculture) & Pine Land Co. (DPL) which are co-inventors on related patents.
The intented application is to protect a company`s investment in developing genetically engineered plants. This is done by preventing farmers from using their seeds for the next year´s planting. Terminator function is achieved by adding three genes to plant. If the seeds from the modified plants are treated with an antibiotic, the plants that grow from those seeds will produce a toxin that renders their seed sterile. So far, the technology has been used only in experimental tobacco plant at a USDA lab.
There has been many campaing against the technology. Critics claim that it would prevent farmers from saving seeds and that pollen from the plants might sterilize neighboring fields as well.
USDA says that they will not abandon the technology because it is too promising for the department. The patent could be used to turn any gene on and off which is goal of all plant breeding. There are also other beneficial applications, including preventing the spread of genes from genetically modified crops to the wild plants.
The opponents demand that USDA should not use the technology on existing varietis and on all plants that aren´t highly self-pollinating. But USDA will not alone determine the fait of the terminator technology because there are several companies that are pursuing patents on similar technologies.
LINKS:
Organizations: Greenpeace
REC
Biotechnology companies: Monsanto
Novartis
Scientific links: Colorado State University
Scientific American |
