File Name: transgenic plants and animals .zip
- Genetically Modified Foods and Social Concerns
- Genetically Modified Foods and Social Concerns
- Genetically modified food
Genetically Modified Foods and Social Concerns
This page has been archived and is no longer updated. It is a more precise technique, but not fundamentally different from genetic selection or crossbreeding in its result. The obvious question is ' Why genetically modify livestock? Piglets grow up to gm more during a 21d lactation Noble et al. Human health is directly affected by the necessity for a sustainable and secure supply of healthful food. Genetic modification of livestock holds the promise to improve public health via enhanced nutrition.
For thousands of years, farmers have improved livestock in order to provide for nutritious, wholesome, and cost-effective animal products. Transgenesis allows improvement of nutrients in animal products, including their quantity, the quality of the whole food, and specific nutritional composition. Transgenic technology could provide a means of transferring or increasing nutritionally beneficial traits. For example, enhancing the omega-3 fatty acid in fish consumed by humans may contribute to a decreased occurrence of coronary heart disease.
In fact, transgenic pigs that contain elevated levels of omega-3 fatty acids have been produced Lai et al. Furthermore, transfer of a transgene that elevates the levels of omega-3 fatty acids into pigs may enhance the nutritional quality of pork Lai et al. The production of lower fat, more nutritious animal products produced by transgenesis could enable improvements in public health.
Over the last few years, livestock production has been under attack as being harmful to the environment. However, the production of transgenic livestock has the potential to dramatically reduce the environmental footprint of animal agriculture.
Increasing efficiency and productivity through transgenesis could decrease the use of limited land and water resources while protecting the soil and ground water. One excellent example of this is the swine the Enviro-Pig TM produced by genetic engineering Golovan et al.
Pigs do not fully utilize dietary phosphorus. Dietary supplementation results in increased production costs, and incomplete utilization results in phosphorus levels in waste products that can cause pollution problems. Golovan et al. The use of phytase transgenic pigs in commercial pork production could result in decreased environmental phosphorus pollution from livestock operations.
Improved production efficiencies of milk and meat would decrease the amount of manure, slow the direct competition for human food, decrease the amount of water required for the animals and the production facilities, and decrease the land necessary for livestock operations.
Advances in transgenic technology provide the opportunity either to change the composition of milk or to produce entirely novel proteins in milk Table 2.
The major nutrients in milk are protein, fat, and lactose. By elevating any of these components, we can impact the growth and health of the developing offspring. Cattle, sheep, and goats used for meat production can benefit from increased milk yield or composition.
In tropical climates, heat-tolerant livestock breeds such as Bos indicus cattle are essential for the expansion of agricultural production. However, Bos indicus cattle breeds do not produce copious quantities of milk. Improvement in milk yield by as little as liters per day may have a profound effect on weaning weights in cattle such as the Nelore or Guzerat breeds in Brazil Figure 2.
Similar comparisons can be made with improving weaning weights in meat-type breeds like the Texel sheep and Boer goat. This application of transgenic technology could lead to improved growth and survival of offspring. The overexpression of beneficial proteins in milk through the use of transgenic animals may improve growth, development, health, and survivability of the developing offspring.
Small improvements in milk volume in Guzerat cows left using genetic material from high-producing Holsteins right could have a significant impact on Brazilian beef production Wheeler et al. The production of transgenic livestock has been instrumental in providing new insights into the mechanisms of gene action implicated in the control of growth, Ebert et al.
It is possible to manipulate growth factors, growth factor receptors, and growth modulators through the use of transgenic technology. Results from one study have shown that an increase in porcine growth hormone GH leads to enhancement of growth and feed efficiency in pigs Vize et al. In the case of fish, there is a need for more efficient and rapid production, without diminishing the wild stocks, to provide a protein source for the increasing world population.
Introduction of salmon GH constructs has resulted in a fold increase in weight after 1 year of growth Devlin et al. This illustrates the point that increased growth rate and ultimately increased protein production per animal can be achieved via transgenic methodology.
Another aspect of manipulating carcass composition is that of altering the fat or cholesterol composition of the carcass. There is also the possibility of introducing beneficial fats such as the omega-3 fatty acids from fish or other animals into our livestock Lai et al. In addition, receptors such as the low-density lipoprotein LDL receptor gene and hormones like leptin are potential targets that would decrease fat and cholesterol in animal products.
Genetic modification of livestock will enhance animal welfare by producing healthier animals. Animal welfare is a high priority for anyone involved in the production of livestock. The application of transgenic methodology should provide opportunities to genetically engineer livestock with superior disease resistance.
One application of this technology is to treat mastitis, an inflammation of the mammary gland, typically caused by infectious pathogen s. Mastitis causes decreased milk production. Transgenic dairy cows that secrete lysostaphin into their milk have higher resistance to mastitis due to the protection provided by lysostaphin, which kills the bacteria Staphylococcus aureus , in a dose-dependent manner Donovan et al.
Lysostaphin is an antimicrobial peptide that protects the mammary gland against this major mastitis-causing pathogen. Recent progress has produced prion-free Richt et al. This is only a partial list of organisms or genetic diseases that decrease production efficiency and may also be targets for manipulation via transgenic methodologies.
Several potential genes have recently been identified that may profoundly affect reproductive performance and prolificacy. Introduction of a mutated or engineered estrogen receptor ESR gene could increase litter size in a number of diverse breeds of pigs.
A single major autosomal gene for fecundity, the Boroola fecundity FecB gene , which allows for increased ovulation rate, has been identified in Merino sheep Piper et al.
Each copy of the gene has been shown to increase ovulation rate by approximately 1. Production of transgenic sheep containing the appropriate FecB allele could increase fecundity in a number of diverse breeds. The manipulation of reproductive processes using transgenic methodologies is only beginning and should be a rich area for investigation in the future.
The control of the quality, color, yield, and even ease of harvest of hair, wool, and fiber for fabric and yarn production has been another area of focus for transgenic manipulation in livestock. The manipulation of the quality, length, strength, fineness, and crimp of the wool and hair fiber from sheep and goats has been examined using transgenic methods Hollis et al. In the future, transgenic manipulation of wool will focus on the surface of the fibers. Decreasing the surface interaction could decrease shrinkage of garments made from such fibers.
Recently, a novel approach to producing spider silk , a useful fiber, has been accomplished using the milk of transgenic goats Karatzas et al. Spiders that produce orb-webs synthesize as many as seven different types of silk for making these webs. One of the most durable varieties is dragline silk. Its energy-absorbing capabilities exceed those of steel. There are numerous potential applications of these fibers in medical devices, sutures, ballistic protection, tire cord, air bags, aircraft, automotive composites, and clothing.
In using any new technology, there are problems that occur and there are risks to be considered. From the technical side, these problems can be: 1 unregulated expression of genes resulting in over- or underproduction of gene products; 2 too high a copy number resulting in overexpression of products; 3 possible side effects, e.
Many, if not all, of these problems are related to the transgene itself, integration site, copy number, and transgene expression. These issues can be addressed, at least in part, through construct design and testing. From the animal side, the welfare, biology, and health of the resulting transgenic animal must be of paramount concern.
From the consumer side, the food or agricultural product produced must be safe, wholesome, non-allergenic, nutritious, and economical. These are issues being addressed by various governmental agencies. The genetic engineering of livestock is a difficult task, and great care must be taken before such effort begins. Serious consideration is critical because of the time, cost, welfare, ethics, risks, and benefits involved in these kinds of projects.
However, farmers, consumers, and scientists all want safe food, which means that animal care, animal health, animal welfare, public concern, ethics, and societal benefit and vigilance cannot be ignored. On the contrary, these concerns should be welcomed when designing and conducting such projects.
Consideration of these as well as scientific issues will lead us forward toward harvesting the bounty promised by this important technology. Boroola fecundity FecB gene : A single major autosomal gene for fecundity in Merino sheep. Creutzfeldt-Jacob disease CJD : A progressive neurological disease in humans caused by a transmissible agent known as a prion.
EGF : Epidermal growth factor, which is a growth factor involved in cell growth, proliferation, and differentiation. IGF-I : Insulin-like growth factor-I, which is a growth factor involved in neonatal growth and anabolic growth in adults.
This is the same disease as bovine spongiform encephalopathy BSE. Staphylococcus aureus : A gram-positive bacterium that is a major causative agent of mastitis in cattle. Such an organism is able to pass the transgene on to all the offspring. It should be stressed that all the cells of a transgenic individual contain the transgene. Also, the original transgenic individual had the foreign DNA inserted into the one-cell embryo via a laboratory technique, such as pronuclear injection.
It could be a microbe, plant, or animal. Devlin, R. Production of germline transgenic Pacific salmonids with dramatically increased growth performance. Canadian Journal of Fisheries and Aquatic Sciences 52 , Extraordinary salmon growth . Nature , Donovan, D. Engineering disease resistant cattle. Transgenic Research 14 , Dunham, R. Comparison of traditional breeding and transgenesis in farmed fish with implications for growth enhancement and fitness. Transgenic Animals in Agriculture ,
Genetically Modified Foods and Social Concerns
Biotechnology is providing us with a wide range of options for how we can use agricultural and commercial forestry lands. The cultivation of genetically modified GM crops on millions of hectares of lands and their injection into our food chain is a huge global genetic experiment involving all living beings. Considering the fast pace of new advances in production of genetically modified crops, consumers, farmers and policymakers worldwide are challenged to reach a consensus on a clear vision for the future of world food supply. The current food biotechnology debate illustrates the serious conflict between two groups: 1 Agri-biotech investors and their affiliated scientists who consider agricultural biotechnology as a solution to food shortage, the scarcity of environmental resources and weeds and pests infestations; and 2 independent scientists, environmentalists, farmers and consumers who warn that genetically modified food introduces new risks to food security, the environment and human health such as loss of biodiversity; the emergence of superweeds and superpests; the increase of antibiotic resistance, food allergies and other unintended effects. This article reviews major viewpoints which are currently debated in the food biotechnology sector in the world.
Genetic engineering of plants represents the next stage of evolution in our continuing efforts to improve plants used for the production of food and animal feed.
Genetically modified food
The human population has reached 7 billion by and is estimated to exceed 10 billion by the end of As such, crops which are the main food source must be produced at a higher pace in order to cater in tandem with the food demand. In the past, traditional plant breeders practice classical breeding techniques to propagate plants with desirable traits. However, traditional breeding technique lies in that only individuals of the same or closely related species can be crossbred.
Терпкий аромат красного вина ударил в ноздри Беккера, когда падре Херрера опустил перед ним серебряную, отполированную миллионами рук чашу. Немного рано для алкогольных напитков, подумал Беккер, наклоняясь. Когда серебряный кубок оказался на уровне его глаз, возникло какое-то движение, и в полированной поверхности смутно отразилась приближающаяся фигура.
Одним быстрым движением она выпрямилась, выпустила струю прямо в лицо Беккеру, после чего схватила сумку и побежала к двери. Когда она оглянулась, Дэвид Беккер лежал на полу, прижимая ладони к лицу и корчась от нестерпимого жжения в глазах. ГЛАВА 71 Токуген Нуматака закурил уже четвертую сигару и принялся мерить шагами кабинет, потом схватил телефонную трубку и позвонил на коммутатор. - Есть какие-нибудь сведения о номере? - выпалил он, прежде чем телефонистка успела сказать алло. - Пока ничего, сэр.