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| 1. |
Describe the benefits of transgenic animals. |
| Answer» <p>The benefits of these animals to human welfare can be grouped into areas:</p><p>AgricultureMedicineIndustryThe examples below are not intended to be complete but only to provide a sampling of the benefits.</p><p>1. Agricultural Applications</p><p>Transgenesis will allow larger herds with specific traits.a) breeding Farmers have always used selective breeding to produce animals that exhibit desired traits (e.g., increased milk production, high growth rate).11,15,17 Traditional breeding is a time-consuming, difficult task. When technology using molecular biology was developed, it became possible to develop traits in animals in a shorter time and with more precision. In addition, it offers the farmer an easy way to increase yields.</p><p>Scientists can improve the size of livestock genetically.b) quality Transgenic cows exist that produce more milk or milk with less lactose or cholesterol12, pigs and cattle that have more meat on them8,17, and sheep that grow more wool18. In the past, farmers used growth hormones to spur the development of animals but this technique was problematic, especially since residue of the hormones remained in the animal product.</p><p>Disease-resistant livestock is not a reality just yet.c) disease resistance Scientists are attempting to produce disease-resistant animals, such as influenza-resistant pigs, but a very limited number of genes are currently known to be responsible for resistance to diseases in farm animals.</p><p>2. Medical Applications</p><p>Transplant organs may soon come from transgenic animals.a) xenotransplantation Patients die every year for lack of a replacement heart, liver, or kidney. For example, about 5,000 organs are needed each year in the United Kingdom alone. Transgenic pigs may provide the transplant organs needed to alleviate the shortfall.9 Currently, xenotransplantation is hampered by a pig protein that can cause donor rejection but research is underway to remove the pig protein and replace it with a human protein.</p><p>3. Industrial Applications</p><p>In 2001, two scientists at Nexia Biotechnologies in Canada spliced spider genes into the cells of lactating goats. The goats began to manufacture silk along with their milk and secrete tiny silk strands from their body by the bucketful. By extracting polymer strands from the milk and weaving them into thread, the scientists can create a light, tough, flexible material that could be used in such applications as military uniforms, medical microsutures, and tennis racket strings.</p><p>Toxicity-sensitive transgenic animals have been produced for chemical safety testing. Microorganisms have been engineered to produce a wide variety of proteins, which in turn can produce enzymes that can speed up industrial chemical reactions</p> | |