Transgenic animals:

Animals that have had their DNA manipulated to possess and express an extra gene are known as transgenic animals. They are produced by following method:

A) Study of normal physiology and development:

• It is important to study the regulation of genes and how they affect the normal functions of the body and its development.
• For example; study of complex factors involved in growth such as insulin-like growth factor

B) Study of disease:

• It is important to study the genes which are responsible for disease in humans and their treatments.
• Transgenic models exist for many human diseases such as cancer, cystic fibrosis, rheumatoid arthritis and Alzheimer’s.

C) Biological products:

• Transgenic animals that produce useful biological products can be created by the introduction of the portion of DNA which codes for a particular product such as human protein (α-1-antitrypsin) used to treat emphysema.
• Similar attempts are being made for treatment of phenyl-ketonuria  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.

d) Vaccine safety:

• Transgenic mice are being developed for use in testing the safety of vaccines before they are used on humans.
•  Like in case of polio vaccine.

 

e) Chemical safety testing:

• Transgenic animals are exposed to the toxic substances and their effects are well studied.
• Time taken is very small to check reactivity of material.