Animals that have had their DNA manipulated to possess and express an extra (foreign) gene are known as transgenic animals or Genetically Engineered Animals.
Various applications of transgenic animals are:
• Study of normal physiology and development:
Transgenic animals can be specifically designed to allow the study of how genes are regulated, and how they affect the normal functions of the body and its development, e.g., study of complex factors involved in growth such as insulin-like growth factor.
• Study of diseases: Many transgenic animals are designed to increase our understanding of how genes contribute to the development of diseases. Transgenic models exist for many human diseases such as cancer, cystic fibrosis, rheumatoid arthritis and Alzheimer’s disease.
Production of biological products using Transgenic Animals:
Transgenic animals that produce useful biological products can be created by the introduction of the portion of DNA (or genes) which codes for a particular product such as human protein (a-1-antitrypsin) used to treat emphysema. Similar attempts are being made for treatment of phenylketonuria (PKU) and cystic fibrosis. In 1997, the first transgenic cow, Rosie, produced human protein-enriched milk (2.4 grams per litre). The milk contained the human alpha- lactalbumin and was nutritionally a more balanced product for human babies than natural cow-milk.
• Vaccine safety testing : Transgenic mice are being developed for use in testing the safety of vaccines before they are used on humans. Transgenic mice are being used to test the safety of the polio vaccine.
• Chemical safety testing : Transgenic animals carry genes which make them more sensitive to toxic substances than non-transgenic animals. They are then exposed to the toxic substances and the effects are studied. Toxicity testing in such animals will allow us to obtain results in less time.
Now so that you have learnt What Are Some Transgenic Animals and facts about transgenic animals, you will easily understand the Transgenic Animals Pros and Cons.