- Animals that have had their DNA manipulated to possess and express a foreign gene are known as transgenic animals. Example- Transgenic rats, rabbits, pigs, sheep etc.
- Transgenic animals are created-
- To study how genes are regulated, and how they affect the normal functions of the body and its development. Example- study of complex factors involved in growth such as insulin-like growth factor.
- to study how genes contribute to the development of disease.
- to produce biological products such as human protein (α-1-antitrypsin) used to treat emphysema, proteins to treat phenylketonuria and cystic fibrosis, human alpha-lactalbumin enriched milk. Example- the first transgenic cow, Rosie, produced human protein-enriched milk 2.4 grams per litre.
- for testing the safety of vaccines before they are used on humans. Example- Transgenic mice are being used to test the safety of the polio vaccine.
- for testing toxicity of drugs.
Fig. transgenic cow, Rosie