Modern biotechnological advances have provided the ability to tap into a natural resource, theworld gene pool,with such great potential that its full magnitude is only beginning to be appreciated.
Theoretically, it should be possible to transfer one or more genes from any organism in the world into any other organism. Because genes ultimately control how any organism functions, gene transfer can have a dramatic impact on agricultural resources and human health in the future.
History of Biotechnology
Although the term “biotechnology” is relatively new, the practice of biotechnology is at least as old as civilization. Civilization did not evolve until humankind learned to produce food crops and domestic livestock through the controlled breeding of selected plants and animals. Eventually humans began to utilize microorganisms in the production of foods such as cheese and alcoholic beverages.
During the twentieth century, the pace of modification of various organisms accelerated. Through carefully controlled breeding programs, plant architecture and fruit characteristics of crops have been modified to facilitate mechanical harvesting. Plants have been developed to produce specific drugs or spices, andmicroorganisms have been selected to produce antibiotics and other medicinal or food products.
Developments in Biotechnology
Since the mid-twentieth century, the ability to utilize artificial media to propagate plants has led to the development of a technology called tissue culture. The earliest formof tissue culture involved using the culture of meristem tissue to produce numerous tiny shoots that can be grown into full-size plants, referred to as clones because each plant is genetically identical.
|Developments in Biotechnology|
The callus tissue can be separated into single cells to establish a cell suspension culture. Callus tissue and cell suspensions can be used to produce specific drugs and other chemicals. Entire plants can also be generated from the callus tissue or from single cells by addition of specific combinations of hormones.
Afar more complex method of cloning of plants and animals from the deoxyribonucleic acid (DNA) of a single cell is amore recent development. Proponents of this method of producing copies of organisms have suggested that cloning technology might be used to improve agricultural stock and to regenerate endangered species.
These ideas have had their detractors, however, as critics have noted the potential dangers of narrowing a species’ gene pool. The July, 1996, birth in Scotland of Dolly, a sheep cloned and raised to adulthood, demonstrated that the cloning of animals had left the realm of science fiction and become a matter of scientific fact.
Recombinant DNA Technology
In practice, recombinant DNA methodology is complex, but in concept, it is fairly easy to comprehend. The genes in all living cells are composed of the same chemical, DNA. The DNA of all cells, whether from bacteria, plants, or animals including humans, is very similar. When DNA from a foreign species is transferred into a different cell, it functions exactly as the native DNA functions; that is, it "codes" for protein.
The easiestway to manipulate genes is using bacterial cells (most often Escherichia coli) and a vector, an agent that can be used to pass the gene fromone cell to another. Plasmids, small extra circular DNA molecules found in many bacterial cells, are commonly used for this purpose. Plasmids are replicated along with the bacterial cell’s own DNA every time the cell reproduces. Plasmids can be easily isolated from bacterial cells.
|Recombinant DNA Technology|
Although expressing foreign genes in bacterial cells is relatively simple, inserting theminto plants and getting them expressed is more complicated. The Ti plasmid is a widely used vector that works well in dicots but has never worked for monocots. Consequently, the first successful transgenic plants were dicots, while success with the most important food crops, monocots such as rice and corn, took more time and effort.
Many alternative methods for inserting genes into plant cells have been developed that work on both monocots and dicots. Microinjection can be used to insert a gene into individual cells. A less laborious method is called biolistic, for biological ballistic, where millions of copies of the gene are attached to tiny projectiles that are then fired into groups of plant cells. Using these and other methods, genetic modification of plants is becoming more routine.
Future of Biotechnology in Agriculture
This new technology could have a tremendous impact on agriculture. As the human population grows, biotechnology will most likely play an important role in producing an increase in food production. Such an increase will require developments such as crop plants that will produce higher yields under normal conditions and crops that will produce higher yieldswhen grown inmarginal environments.
Biotechnology provides a means of developing higher-yielding crops in much less time than it takes to develop them though traditional plant-breeding programs. Genes for the desired characteristics can be inserted directly into the plant without having to go through repeated controlled selection and breeding cycles to establish the trait.
There are also economic advantages in diversifying agriculture production in a given area. A producer might wish to grow a particular high-value cash crop in an area where soil or climate conditions would prevent such a crop from thriving. Biotechnology can help solve these types of problems. For example, high value crops can be developed to grow in areas that heretofore would not have supported such crops.
Plants also can be developed to produce new products such as antibiotics, drugs, hormones, and other pharmaceuticals. Crop plants bioengineered to produce novel products mean that pharmaceuticals and other valuable products could be grown in farm environments rather than in laboratories.
While there will be a growing pressure for agriculture to produce more food in the future, there will also be pressure for crop production to be more friendly to the environment. Biotechnology has the potential to play a major role in the development of a long-term, sustainable, environmentally friendly agricultural system. For example, the development of crop varieties with improved resistance to pests will reduce the reliance on pesticides.
Methods of crop production and harvestwith less environmental impact will also have to be developed. Because agriculture will continue to have an impact on the environment, the need to remediate polluting agents will continue to exist. Hence biotechnology will play an important role in the development of bioremediation systems for agriculture as well as other industrial pollutants.
There will be many difficult ethical and economic issues surrounding the use of this new biotechnology. One of the major questions concerns ownership. Patent laws in the United States read that ownership over an organism can be granted if the organism has been intentionally genetically modified through the use of recombinant DNA techniques.
In addition, processes that utilize genetically modified organisms can be patented. Therefore one biotechnology firm may own the patent to an engineered organism, but another firm may own the rights to the process used to produce it.