Medications of the future may be made to order–short order from the griddle, that is. Scientists have genetically engineered chickens so that they produce foreign proteins in eggs. This is an important step toward the goal of routinely breeding hens that lay packages of pharmaceuticals.
Starting in the 1980s, scientists have created a variety of ready-made animal drug factories. Genetically altered cows, pigs, sheep, goats, rabbits, and mice and have manufactured foreign proteins in mammary tissue. The researchers harvest the milk of these animals and extract therapeutic substances such as blood-clotting agents and insulin.