. T RANSGENIC A NIMALS Animals that have had their DNA manipulated to possess and express an extra (foreign) gene are known as transgenic animals . Transgenic rats, rabbits, pigs, sheep, cows and fish have been produced, although over per cent of all existing transgenic animals are mice. Why are these animals being produced?
How can man benefit from such modifications ? Let us try and explore some of the common reasons: 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. By introducing genes from other species that alter the formation of this factor and studying the biological effects that result, information is obtained about the biological role of the factor in the body. Study of disease: Many transgenic animals are designed to increase our understanding of how genes contribute to the development of disease.
These are specially made to serve as models for human diseases so that investigation of new treatments for diseases is made possible. Today transgenic models exist for many human diseases such as cancer, cystic fibrosis, rheumatoid arthritis and Alzheimer’s.