Transgenic animals are produced for several reasons. Which of the following pairs of a reason and its example, as given in NCERT, is correctly matched?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Normal physiology and development – Study of insulin-like growth factor
NCERT gives five reasons for making transgenic animals: normal physiology and development, study of disease, biological products, vaccine safety and chemical safety testing. Each reason has its own example, and the question mixes these examples up.
Option (1) Normal physiology and development – Study of insulin-like growth factor — Correct. Genes from other species that alter the formation of insulin-like growth factor are put into the animal, and the effects tell us the role of this factor in growth.
Option (2) Vaccine safety – Models for rheumatoid arthritis — Incorrect. Models for rheumatoid arthritis (and cancer, cystic fibrosis, Alzheimer’s) come under study of disease.
Option (3) Study of disease – Testing the safety of polio vaccine — Incorrect. Testing the polio vaccine on transgenic mice is the example of vaccine safety. Such mice may one day replace monkeys for this testing.
Option (4) Chemical safety testing – Attempts to treat phenylketonuria (PKU) — Incorrect. Attempts for PKU come under biological products, along with α-1-antitrypsin for emphysema. Chemical safety testing uses animals that are more sensitive to toxic substances.
NCERT Extract:
Transgenic Animals – “… (i) 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. … (ii) Study of disease: … Today transgenic models exist for many human diseases such as cancer, cystic fibrosis, rheumatoid arthritis and Alzheimer’s.”
Transgenic Animals – “… (iii) Biological products: … Similar attempts are being made for treatment of phenylketonuria (PKU) and cystic fibrosis. … (iv) Vaccine safety: … Transgenic mice are being used to test the safety of the polio vaccine. … (v) Chemical safety testing: This is known as toxicity/safety testing.”