cogenomics, genetic testing (and prenatal diagnosis), and gene therapy. These applications
use our knowledge of biology to improve our health and our lives. Many of these medical
applications are based on the findings of the Human Genome Project.
Agriculture
Biotechnology has also led scientists to develop useful applications in agriculture and food
science. These include the development oftransgenic crops- the placement of genes into
plants to give the crop a beneficial trait. Benefits include:
- Improved yield from crops.
- Reduced vulnerability of crops to environmental stresses.
- Increased nutritional qualities of food crops.
- Improved taste, texture or appearance of food.
- Reduced dependence on fertilizers, pesticides and other agrochemicals.
Crops are obviously dependent on environmental conditions. Drought can destroy crop
yields, as can too much rain or floods. But what if crops could be developed to withstand
these harsh conditions? Biotechnology will allow the development of crops containing genes
that will enable them to withstand harsh conditions. For example, drought and excessively
salty soil are two significant factors affecting crop productivity. But there are crops that
can withstand these harsh conditions. Why? Probably because of that plant’s genetics. So
scientists are studying plants that can cope with these extreme conditions, trying to identify
and isolate the genes that control these beneficial traits. The genes could then be transferred
into more desirable crops, with the hope of producing the same phenotypes in those crops.
Thale cress (Figure6.18), a species ofArabidopsis (Arabidopsis thaliana), is a tiny weed
that is often used for plant research because it is very easy to grow and its DNA has been
extensively characterized. Scientists have identified a gene from this plant, At-DBF2, that
gives the plant resistance to some environmental stresses. When this gene is inserted into
tomato and tobacco cells, the cells were able to withstand environmental stresses like salt,
drought, cold and heat far better than ordinary cells. If these preliminary results prove
successful in larger trials, then At-DBF2 genes could help in engineering crops that can
better withstand harsh environments. Researchers have also created transgenic rice plants
that are resistant to a rice virus. In Africa, this virus destroys much of the rice crops and
makes the surviving plants more susceptible to fungal infections.
Lesson Summary
- Using recombinant DNA technology, a foreign gene can be inserted into an organism’s
DNA.