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Chapter 4 Biotechnology and Crop Engineering |
by Donna M. Brinton, Christine Holten, and Jodi L. Nooyen
Background | Classroom Applications | Internet Resources | Appendices
Background
The way that plants are bred has changed completely because of biotechnology and gene research. In fact, scientists can now introduce traits from other plants and even animals into the genetic makeup of a particular plant. Such genetic changes can increase crop yield, change growing patterns, and improve plant taste or health.
Some of the questions this chapter explores include:
- What is crop engineering?
- How has biotechnology changed methods of plant breeding?
- What are the benefits and potential disadvantages of this new technology?
- What will crop engineering mean around
the world?
This chapter will give students a basic understanding of areas in which crop engineering is being used today. It also explores the controversies surrounding genetically modified foods and the different worldwide reactions to this technology. Teachers can use the lesson plans and materials to give students an understanding of these concepts and a command of the vocabulary necessary to discuss them.
Background Information
For more than 10,000 years, farmers
have been experimenting with plants to find the best seeds
to grow plentiful crops.
In the mid 19th century, Gregor
Mendel, an Austrian monk, began scientific experiments to produce
a better pea.
This “new” science of plant breeding allowed scientists not only to grow more plentiful crops but also to create plants that resist insects, disease, and drought. However, since success depended on locating a desirable plant trait and breeding it over a number of years until the ideal plant species was created, this method was very labor intensive and required long periods of time.
Over the past 20 years, biotechnology has dramatically changed methods of plant breeding. Today, biotechnology allows scientists to move specific genes from one species to another to produce changes. It also makes conventional plant breeding more efficient by allowing scientists to select and transfer only genes for desired traits. Plants created using biotechnology are generally referred to as genetically modified (GM) or transgenic plants.
Perhaps the best-known example of a GM plant is golden rice. Created through the efforts of Ingo Potrykus, a professor at the Swiss Federal Institute of Technology in Zurich, this crop was genetically modified to contain beta-carotene (or vitamin A). This vitamin improves the rice’s nutritional value and could improve the lives of millions of people for whom this is a primary food. It was Potrykus’s dream that this enriched golden rice (so-called because of its pale yellow color) would feed hungry children all over the world. Since rice does not naturally contain beta-carotene, Potrykus needed to find a way to change the genetic makeup of normal rice. He and his colleagues introduced genes from daffodils and a bacteria into the genetic code of normal rice. They also “infected” white rice with another bacteria for beta-carotene. This new transgenic rice plant could then be bred with rice that grew well in different climates.
In addition to golden rice, other crops have been produced through biotechnology. These include cotton that has the ability to fight off boll weevils and corn and papaya that resist viruses.
Potrykus’s dream of feeding millions with genetically modified crops is now a reality. Over 60% of foods sold in the United States today contain GM food ingredients. In many developing nations GM foods are improving the nutritional content of what people eat. The benefits are obvious. Before genetic modification, in experiments to produce new plants, scientists used either radiation or powerful chemicals on plants to produce genetic changes. Transgenic technology does not require this dangerous practice, thereby making the GM foods that we eat safer. Farmers who grow plants that have a genetic resistance to insects and disease do not need to use pesticides, which is good for the environment. Additionally, the technology needed to genetically engineer crops also requires little equipment. This means that farmers in developing nations, who are often unable to afford pesticides or expensive farming equipment, can produce and use genetic modification. Finally, transgenic crops can improve the nutritional value of foods, such as rice and corn, which are very important in the diets of people throughout the world. This means that a bowl of golden rice could prevent children in Southeast Asia from getting an eye disease caused by insufficient vitamin A. Similarly, a tortilla made from GM corn could satisfy the daily nutritional needs of a child in Central America, even if fruits, vegetables, or meat were not available. The world’s population is growing, but the amount of land available to grow food is not. Genetic crop engineering might be an important way to improve global health and feed the world’s population by enabling farmers to produce more food more efficiently.
However, GM foods have also been called “Frankenfoods” (after the fictional monster Frankenstein, who is the symbol of uncontrolled and dangerous science). People are beginning to worry that Frankenfoods are harmful to their health and to the environment. One of the biggest concerns is that GM plants could become toxic to human beings. For example, changing some of a plant’s genes could accidentally cause other inactive genes to become active. In a recent case, people who ate a certain brand of corn taco shells complained of becoming violently ill. Their symptoms, which included rashes, diarrhea, and vomiting, are possibly linked to the genetically modified corn used in the taco shells. Another concern is that people who have food allergies (such as nut allergies or shellfish allergies) may accidentally eat a food to which they are allergic. Such accidents have become more likely because scientists sometimes introduce a gene from a nut or a fish into corn to produce a desired trait.
In addition to worries related to human health, critics also worry about the effects on animals and other plants. For example, what if a gene that makes a crop plant insect resistant were passed to a wild plant? This could create “super weeds” that would be difficult if not impossible to kill. What if animals or insects ate GM crops that were toxic to them? In an actual case, butterflies that touched pollen from GM corn either died or developed abnormally. Farmers also worry that insects exposed to insect-resistant GM crops will become immune to the toxin in the crop.
At present there is little scientific evidence that GM crops are a direct danger to human health or to the environment. Further studies need to be done to determine the long-term effects of this technology. In addition, at least in the United States, both manufacturers and the government test GM products before selling them to the public. However, consumers have complained about GM foods, in part because the foods have been modified, but also because they feel the manufacturers are deceiving the public. The manufacturers have not provided clear information about the presence of genetically modified foods through advertising, package labeling, lists of ingredients, and other important consumer information.
Glossary
Allergy: (allergic, adjective) An abnormally high sensitivity to certain substances, such as pollens or foods. Common symptoms may include sneezing, itching, and skin rashes.
Beta-carotene: Gives a reddish color to plants such as carrots and tomatoes. The liver can convert it into vitamin A. Food sources of this vitamin include vegetables such as carrots, sweet potatoes, spinach, and other leafy green vegetables; and fruit such as cantaloupes and apricots (also see vitamin A).
Biotechnology: A set of biological techniques developed through basic research. Now applied to research and product development. In particular, the use by industry of recombinant DNA, cell fusion, and new bioprocessing techniques. Modern biotechnology products include antibiotics, insulin, interferon, and techniques such as waste recycling. Much older forms of biotechnology include breadmaking, cheese making, and brewing wine and beer.
Boll weevil: A worm that infects and kills cotton crops
Breed (v) bred (irregular past tense): To develop new or improved kinds of animals or plants, chiefly through controlled mating and selection of offspring for desirable traits.
Climate: The weather in a location averaged over a long period of time.
Conduct: To do or manage an activity. “Further studies need to be conducted…”
Crop: (1) Cultivated plants (plants planted by farmers) or agricultural produce, such as grains, vegetables, or fruit. (2) The total amount of such produce harvested in a particular season or place.
Crop engineering (or Genetic Crop Engineering): The manipulation of a plant´s genetic makeup by introducing, enhancing, or eliminating specific genes through modern molecular biology techniques.
Crop yield: Total products (e.g. vegetables) resulting from growth or cultivation.
Diarrhea: Frequent and watery bowel movements, often accompanied with stomach pain.
Drought: A long period of abnormally low rainfall, especially one that negatively affects growing or living conditions.
Enrich (v), enriched (adj): To add nutrients to: The dairy enriched its milk with vitamin D.
“Frankenfood” : A negative way to refer to GM foods, named after the fictional monster Frankenstein http://home-1.worldonline.nl/~hamberg/, who is a symbol of “out of control” science.
Gene: A hereditary unit that determines a particular characteristic in an organism. Genes exist in a number of different forms and can undergo mutation.
Gene research: The study of genes and genetics.
Genetic makeup / Genetic code: The entire DNA coding of an organism.
Genetically modified (GM) food (or plant, crop) (n): The agricultural products of genetic engineering technology, for example, the introduction, enhancement, or deletion of particular characteristics in an organism by altering its DNA (genetic makeup). Examples of such modified foods or foods that will likely be modified in the near future include: apples, canola, corn, grapevines, lentils, lettuce, maize, papaya, peas, pineapples, potatoes, soy beans, sugarcane, tomatoes, and wheat.
Genetically modify (v): The use of modern biotechnology to change the genetic makeup of an organism (a plant) by inserting individual gene(s) that have been isolated in the laboratory into the genome of a living organism.
Golden rice: A genetically engineered form of rice (http://www.biotech-info.net/golden.html) which has been infused with vitamin A (a vitamin not usually found in rice).
Gregor Mendel: Founder of the science of genetics (1822-1884). An Austrian monk and botanist. His breeding experiments on garden peas and subsequent formulation of the laws of heredity formed the basis for the study of genetics.
Immune (v) (Immunity, (n): Protected against, infectious disease.
Ingredient: One part of a mixture or recipe.
Insect resistant: Description of a plant that is not affected (or is affected only minimally) by insects.
Monarch butterfly: A type of butterfly common in North America. http://www.learner.org/jnorth/sm/aboutmbsf.html
Nutrition: (1) Foods necessary for a healthy diet. (2) The physical and chemical process by which food is converted into body tissue.
Pollen: The powder produced by seed plants, and most plentiful in Spring. A common cause of allergic reactions.
Pesticide: A chemical that is used to kill unwanted organisms such as rats or weeds. These chemicals often act as nerve poisons, and they are hazardous to animals and humans. Some pesticides can cause nerve or liver damage, birth defects, and cancer in humans.
Plant breeding: The genetic modification of crop plants, with the hopes of improving insect resistance and the nutritional content, as well as creating plants with high yield and enhanced quality.
Plant trait: A genetically determined characteristic of a plant such as its height, resistance to insects and bad weather, and its typical crop yield.
Rash: A skin eruption or reddening of the skin, often with itchiness.
Resistant (adj) Resist (verb) Resistance (noun): (1) Relating to or conferring immunity (to disease or infection) (2) incapable of being affected “disease resistant”.
Seed: The fertilized ripened ovule of a flowering plant containing an embryo and capable normally of germination to produce a new plant.
Shellfish: Any aquatic animal whose external covering consists of a shell, for example, oysters, clams, lobsters, and crabs.
Symptom: Any evidence of disease or of a patient’s condition as perceived by the patient, diagnosis, or a change in a patient’s condition.
Trait: A genetically determined characteristic or condition.
Transgenic: Having genes that have been transferred from another species or breed, for example, a transgenic plant, transgenic rice, transgenic technology, transgenic crops, and transgenic foods.
Transfer (v): The movement of something from one place to another.
Violently ill: Extremely sick.
Vitamin A: A vitamin occurring principally in fish-liver oils, milk, and some yellow and dark green vegetables. Its deficiency causes hardening and roughening of the skin, night blindness, and degeneration of mucous membranes.
Vomit (v): To lose the stomach contents through the mouth, often when feeling ill.
Weed (n): A plant considered undesirable, unattractive, or troublesome, especially one growing where it is not wanted, as in a garden.
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