Introduction to the Issues: Genetically modified organisms




Скачать 46.78 Kb.
НазваниеIntroduction to the Issues: Genetically modified organisms
Дата22.09.2012
Размер46.78 Kb.
ТипДокументы
Introduction to the Issues: Genetically modified organisms


    There are many environmental issues surrounding the agricultural, farming, and ecological applications of biotechnology. Many people question the wisdom of keeping genetically altered livestock, citing the possibility that the altered genes might escape into wild gene pools, where they might have undesirable effects. Objectors to altered crops express similar concerns, also wondering how engineered pest and herbicide resistance might affect local ecology. For example, they ask if herbicide resistance would lead to increased use of dangerous herbicides to kill weeds, since farmers would no longer worry about the dangers of their crops' overexposure to these chemicals. In addition, these people express concern that depriving insects of crops for food would, in turn, deprive birds and frogs of insect prey.

    There are also many objections to the release of genetically engineered organisms into the wild. Environmentalists express misgivings about the effects of introducing new and novel organisms into a given ecological systems. They say that the effects of new organisms - or even ordinary ones with new genes - are too complex to be predicted, and potentially too dangerous to be risked.

Pros and Cons of Genetically Altered Livestock


    Livestock could, in theory, be genetically altered to give maximum output at minimum cost to farmers. Cows could be engineered for high milk production or high meat output, depending on their intended function. Sheep could be engineered for optimum wool growth, and pigs could be altered to have large amounts of meat with a minimum of fat. Advantages of this livestock specification are obvious and immediate: lower costs for manufacturers, lower prices for consumers, and higher output on the part of the animals. Disadvantages are more nebulous: a reduction in genetic diversity; potential and unforeseen health problems from genetically altered products. Some people even object to the ethics of the actual alterations, saying that it is wrong to view animals as production machines for food.

Pros and Cons of Genetically Altered Crops


    Crops could be genetically altered for resistance to drought, frost, pests, disease, and herbicides. As stated above, there are many questions about the ecological impact of these alterations. The addition of any genes into crops could result in these genes' escape into the wild. (This is more of a danger for crops, whose seeds could spread off the farm, than it is for livestock.) Ecologists are uneasy about adding herbicide resistance to crops, fearing that this will eliminate any desire on the part of the farmers to refrain from using too many chemica ls, which could affect wild animals. In addition, the concern exists that disease resistance could cause relatively harmless diseases to mutate and become more dangerous, perhaps even infecting humans. Pest resistance also could kill off insects, depriving birds and frogs of food, which could lead to a dangerous imbalance in the ecology of an area.

Health Problems Associated with Transgenic Livestock and Crops


    Scientists are always searching for genes coding for enzymes and proteins that can be profitably spliced into livestock and crops. These genes confer pest and disease resistance and tolerance of pollution, and often increase the lifespan of livestock or growth rate of crops. However, there are certain health risks involved in this practice. For example, some people have a food allergy known as favism that causes an adverse reaction to the protein lectin, found in beans and other leguminous crops. Since lectin discourages aphids, common insect pests, from feeding on beans, the gene for making lectin has recently been engineered into potatoes. People with favism, unknowingly eating these transgenic potatoes, could have an allergic reaction to them.

    Other health concerns include the question that antibiotic resistance, engineered into foods as a marker, might transfer to the consumers eating the food. These resistant genes could be incorporated into bacteria, against whose diseases we would then be defenseless. (Scientists are working on more benign markers, such as color change or metabolic deficiencies.)

Labeling Transgenic Foods


    To prevent the health problems described above, transgenic foods should always be labeled as such, with added enzymes or proteins listed clearly. Currently, transgenic foods are not required to be separated from ordinary crops and livestock. As a result, the health problems delineated above could potentially occur.

Genetic Engineering Helps the Environment


    The planetary environment today is highly polluted by chemicals, heavy metals, oil products, and various other pollutants. Genetic engineering could change that. Already, genetically engineered oil-consuming bacteria have been released into the wild to clean up disastrous oil spills at sea and on land. Microbes that break down toxic pollutants and heavy metals commonly found near industrial sites have often been researched. These processes, called bioremediation, represent a fraction of what has been called "the most cost-effective means of ridding the earth of its accumulated pollutants". (Biotechnology Unzipped: Promises and Realities, by Eric S. Grace) Genetically engineered microbes can also be used to: monitor environmental conditions in highly polluted areas; add to the output of low-grade mines by filtering precious metals from other substances; clean up contaminated areas around worked-out mines; and decontaminate areas of low-level nuclear waste.

Concerns Regarding the Release of Transgenic Organisms Into the Wild

Many ecologists strongly object to the release of transgenic organisms into the wild, citing loss of genetic diversity, contamination of wild gene pools, and potential mutations as reasons. They say that engineering, say, a human gene into a microbe and releasing it into the environment contaminates the microbial species' natural gene pool. If the human gene is successful or beneficial in the wild, it could spread through the population, eliminating natural genes. Also, since microbial species often exchange genes through rings of DNA called plasmids, the concern exists that the gene could find its way into another species and there mutate, forming a new and novel disease against which humanity has no defense. Though these risks are small, they do exist, and thorough testing of transgenic species to be released should be carried out before the release.

Environmental Issues: Ethical Principles


  • Transgenic livestock and crops are ethically acceptable, but they should be thoroughly tested for safety. The original genome of all altered organisms should be kept on file to protect genetic diversity.

  • Transgenic foods should always be labeled to guard against potential health problems. These labels should enumerate the foreign enzymes and proteins in the food, so that those people with food allergies can avoid ingesting chemicals to which they are allergic.

  • Stocks of original, natural crops and livestock should be maintained and produced for those who have health or personal reasons to avoid eating transgenic foods.

  • The use of transgenic microbes and microbial products in the reduction of pollution is not only ethically acceptable, but it should be encouraged. It is a promising, cost-efficient way to rid the earth of pollutants, and should be pursued.

  • The release into the wild of transgenic organisms should be avoided if possible, to protect against possible ramifications. Transgenic organisms should be tested thoroughly before release into the wild if it proves necessary.

Похожие:

Introduction to the Issues: Genetically modified organisms iconLimited and controlled release of sugarcane genetically modified for altered sugar production

Introduction to the Issues: Genetically modified organisms iconApplication for licence for dealings involving an intentional release of a genetically modified organism into the environment

Introduction to the Issues: Genetically modified organisms iconThis document provides an overview of baseline biological information relevant to risk assessment of genetically modified forms of the species that may be

Introduction to the Issues: Genetically modified organisms iconThis document provides an overview of baseline biological information relevant to risk assessment of genetically modified forms of the species that may be

Introduction to the Issues: Genetically modified organisms iconCommercial release of canola genetically modified for herbicide tolerance and a hybrid breeding system (InVigor® X Roundup Ready® canola)

Introduction to the Issues: Genetically modified organisms iconS3 Students will investigate the habitats of different organisms and the dependence of organisms on their habitat

Introduction to the Issues: Genetically modified organisms iconIntroduction of Issues for Excimer Laser Guidance

Introduction to the Issues: Genetically modified organisms iconFinancial issues, about accommodation, employment, health and welfare, visa or immigration issues

Introduction to the Issues: Genetically modified organisms iconMolecular circuits for associative learning in single-celled organisms

Introduction to the Issues: Genetically modified organisms iconWetland connectivity: understanding the dispersal of organisms that occur in Victoria’s wetlands draft

Разместите кнопку на своём сайте:
Библиотека


База данных защищена авторским правом ©lib.znate.ru 2014
обратиться к администрации
Библиотека
Главная страница