Health and Medicine

How can recombinant-DNA technology improve human health?

Biotechnology, in its broadest sense, has always been part of medicine. Early physicians extracted substances from plants and animals to cure their patients. Twentieth-century medicine saw the use of vaccination to save countless lives. Today, recombinant-DNA technology is the source of some of the most important and exciting advances in the prevention and treatment of disease.

Preventing Disease One interesting development in transgenic technology is golden rice, shown in Figure 15–15. This rice contains increased amounts of provitamin A, also known as beta-carotene—a nutrient that is essential for human health. Provitamin A deficiencies produce serious medical problems, including infant blindness. There is hope that provitamin A-rich golden rice will help prevent these problems. Other scientists are developing transgenic plants and animals that produce human antibodies to fight disease.

FIGURE 15–15 Vitamin-Rich Rice Golden rice is a GM plant that contains increased amounts of provitamin A, or beta-carotene. Two genes engineered into the rice genome help the grains produce and accumulate beta-carotene. The intensity of the golden color indicates the concentration of beta-carotene in the edible part of the rice seed.

In the future, transgenic animals may provide us with an ample supply of our own proteins. Several laboratories have engineered transgenic sheep and pigs that produce human proteins in their milk, making it easy to collect and refine the proteins. Many of these proteins can be used in disease prevention.

Medical Research Transgenic animals are often used as test subjects in medical research. In particular they can simulate human diseases in which defective genes play a role. Scientists use models based on these simulations to follow the onset and progression of diseases and to construct tests of new drugs that may be useful for treatment. This approach has been used to develop models for disorders like Alzheimer's disease and arthritis.

Treating Disease When recombinant-DNA techniques were developed for bacteria, biologists realized almost immediately that the technology held the promise to do something that had never been done before—to make important proteins that could prolong and even save human lives. For example, human growth hormone, which is used to treat patients suffering from pituitary dwarfism, was once scarce. Human growth hormone is now widely available because it is mass-produced by recombinant bacteria. Other products now made in genetically engineered bacteria include insulin to treat diabetes, blood-clotting factors for hemophiliacs, and potential cancer-fighting molecules such as interleukin-2 and interferon.

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