Q.(a) What are transgenic animals?

Transgenic animals — those whose genome has been deliberately altered by introducing foreign DNA — have been created in the largest numbers as mice, and are used for a range of purposes including studying normal physiology, modelling human disease, and producing useful biological products.

1. Transgenic animals: Animals that have had their genome (DNA) altered/manipulated to possess an additional, modified or foreign gene are called transgenic animals. This is done through genetic engineering techniques that introduce, delete, or otherwise change genetic material, and the introduced change is passed on to the animal's progeny as well.
2. Animal with the largest number of transgenics: Mice are the transgenic animals that have been produced in by far the largest numbers, as they are easy to breed, have a short generation time, and are extensively used as experimental/model organisms.
3. Purposes of producing transgenic animals (any three):

1. Study of normal physiology and development: Transgenic animals are 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., studying complex factors involved in growth, such as insulin-like growth factor.
2. Study of disease: Transgenic animals are engineered to serve as models for various human diseases (e.g. cancer, cystic fibrosis, rheumatoid arthritis, Alzheimer's disease), allowing researchers to study the disease process and to test new/potential treatments before they are used on humans. …