Which of the following is an application of genetic engineering in animals?

• A. Sheep produce a protein for blood clotting required by haemophiliacs
• B. Bacteria make insulin
• C. Weed-killer resistant crops
• D. Fertilizer-enhanced crops

Answer: (A)

Genetic engineering can turn animals into biofactories that produce human proteins in their milk. In this example, a gene for a blood-clotting protein used by haemophiliacs is inserted into sheep so that the protein is made and secreted in the milk. The protein can then be purified for medical use, providing a practical therapy produced in an animal system. This demonstrates an animal-based application because the production occurs in the animal itself, rather than in microbes or plants. Bacteria making insulin is also genetic engineering but in microbes, not animals. The remaining options involve crops, which are plants. So the sheep producing a clotting protein in milk is the correct animal-based application.