Transgenic animals at work, and the worries

Transgenic animals can serve as living bioreactors: molecular pharming means making valuable proteins in an animal, usually in its milk, from which they are easy to collect.

• Tracy the ewe made human α1-antitrypsin in her milk. People who lack this protein develop lung disease (emphysema). But clinical trials showed side effects.
• Rosie the cow (1997) gave milk enriched with human α-lactalbumin, closer to human milk.
• Other proteins made in milk: albumin (cow), α-fetoprotein, growth hormone and tissue plasminogen activator (goat), clotting factor IX (mouse), and clotting factor VIII (rabbit).

Transgenic animals also help research: animals made to develop human diseases such as cancer or Alzheimer's show how genes work and how diseases progress. And they are used to test the safety (toxicity) of vaccines, drugs and chemicals before people use them.

The worries. Genetic modification is powerful, so it carries risks:

• New proteins in food may cause allergies.
• Viral vectors and promoters might cause infections.
• GMOs might escape and become invasive, upsetting ecosystems.
• A gene inserted at a random place might have unpredictable effects.

In India, the Genetic Engineering Appraisal Committee (GEAC), under the Ministry of Environment, Forest and Climate Change, regulates the making, use, import, export and storage of GMOs.