Teaching about Genetic Engineering

Article excerpt

The current world population is 6 billion and the United Nations estimates that by 2030 it will increase to 10 billion (1). Usable farmland will shrink while other land use demands will increase. Some estimates indicate that world food production will have to double on existing farmland over the next 30 years to keep pace with anticipated growth (1). Our food will need to be grown under non-optimal conditions, such as less water and poorer soil, yet it will need to have added nutrition to adequately feed the populace. The biggest question facing agriculture today is how do we provide an increasing population with sufficient quantities of nutritious food while limiting the environmental impact? For agriculture to be sustainable, our food and fiber crops will have to be selected and engineered for optimal efficiency. Genetic engineering is a primary means to accomplish that.

Why Teach About Genetic Engineering?

If you are just now wondering whether you should be teaching about genetic engineering in crop production, you are already too late. According to a recent issue of Science (2), one-half of the 72 million acres of soybeans planted in the U.S. in 1999 were genetically modified. The genie is out of the bottle; the molecular genetic green revolution is here.

So, why teach about genetic engineering of crops in agricultural education? The answer is: because our students represent not only American agriculture, but the American public. The public needs to understand the technology and the implications for the use of this technology in order to make educated decisions regarding these crops and their products. A recent U.S. Senate subcommittee report stated that the Administration, industry, and the scientific community have a joint "responsibility to educate the public and improve the availability of information on the long record of the safe use of agricultural biotechnology products and research activities" (3). The public, including those in agriculture and those who are consumers of agriculture, need to know that:

genetic engineering of food and fiber crops is being done,

plants are being used to produce important industrial and pharmaceutical proteins,

specifically what it is that is being done, how its being done, and what the real concerns are, based on science and reason.

What is Genetic Engineering of Crops?

In conventional breeding, plants with desired characteristics are crossed and the characteristics are selected. This may take many generations over many growing seasons. Humans have conducted traditional plant breeding for thousands of years; and every crop available today is a product of this genetic manipulation. It is time-consuming and imprecise, and the breeder may have little control over the outcome. Plant biotechnology consists of techniques that allow scientists to identify, isolate, and transfer specific genes (DNA fragments) into plants to create desired traits or effects in the plant; it is a very precise genetic modification.

Biotechnologists follow specific steps to create a genetically modified (GM) or engineered plant (See above). The first step is to identify the trait, phenotype or characteristic to be manipulated. Examples include insect resistance or the ability to metabolize excess lead from the soil. Genes for these traits define which particular proteins are made and when, and the proteins cause the desired effect in the plant. Biotechnologists identify the gene that encodes for the desired protein from a source, then clone it (copy and purify it) as a DNA fragment. After the gene is cloned, it must be put into the plant for expression. While there are different ways to accomplish this, the common method of "transformation" of the recipient plant cells is to use a bacterium, Agrobacterium tumefaciens, to temporarily infect the plant. The bacteria delivers the gene into the plant genome.

Once the plant has gone through the transformation process, those plant cells, which do carry your gene of interest, must be selected. …