The below mentioned article will highlight the three important applications of recombinant DNA technology.
The three important applications are: (1) Applications in Crop Improvement (2) Applications in Medicines and (3) Industrial Applications.
I. Applications in Crop Improvement:
Genetic engineering has several potential applications in crop improvement, such as given below:
1. Distant Hybridization:
With the advancement of genetic engineering, it is now possible to transfer genes between distantly related species. The barriers of gene transfer between species or even genera have been overcome. The desirable genes can be transferred even from lower organisms to higher organisms through recombinant DNA technology.
2. Development of Transgenic Plants:
Genetically transformed plants which contain foreign genes are called transgenic plants. Resistance to diseases, insects and pests, herbicides, drought; metal toxicity tolerance; induction of male sterility for plant breeding purpose; and improvement of quality can be achieved through this recombinant DNA technology. BT-cotton, resistant to bollworms is a glaring example.
3. Development of Root Nodules in Cereal Crops:
Leguminous plants have root-nodules which contain nitrogen fixing bacteria Rhizobium. This bacteria converts the free atmospheric nitrogen into nitrates in the root nodules. The bacterial genes responsible for this nitrogen fixation can be transferred now to cereal crops like wheat, rice, maize, barley etc. through the techniques of genetic engineering thus making these crops too capable of fixing atmospheric nitrogen.
4. Development of C4 Plants:
Improvement in yield can be achieved by improving the photosynthetic efficiency of crop plants. The photosynthetic rate can be increased by conversion of C3 plants into C4 plants, which can be achieved either through protoplasm fusion or recombinant DNA technology C4 plants have higher potential rate of biomass production than C3 plants. Most C4 plants (sorghum, sugarcane, maize, some grasses) are grown in tropical and subtropical zones.
II. Applications in Medicines:
Biotechnology, especially genetic engineering plays an important role in the production of antibiotics, hormones, vaccines and interferon in the field of medicines.
1. Production of Antibiotics:
Penicillium and Streptomyces fungi are used for mass production of famous antibiotics penicillin and streptomycin. Genetically efficient strains of these fungi have been developed to greatly increase the yield of these antibiotics.
2. Production of Hormone Insulin:
Insulin, a hormone, used by diabetics, is usually extracted from pancreas of cows and pigs. This insulin is slightly different in structure from human insulin. As a result, it leads to allergic reactions in about 5% patients. Human gene for insulin production has been incorporated into bacterial DNA and such genetically engineered bacteria are used for large scale production of insulin. This insulin does not cause allergy (see figure 1.6).
3. Production of Vaccines:
Vaccines are now produced by transfer of antigen coding genes to disease causing bacteria. Such antibodies provide protection against the infection by the same bacteria or virus.
4. Production of Interferon:
Interferon’s are virus-induced proteins produced by virus-infected cells. Interferon are antiviral in action and act as first line of defense against viruses causing serious infections, including breast cancer and lymph nodes malignancy. Natural interferon is produced in very small quality from human blood cells. It is thus very costly also. It is now possible to produce interferon by recombinant DNA technology at much cheaper rate.
5. Production of Enzymes:
Some useful enzymes can also be produced by recombinant DNA technique. For instance, enzyme urikinase, which is used to dissolve blood clots, has been produced by genetically engineered microorganisms.
6. Gene Therapy:
Genetic engineering may one day enable the medical scientists to replace the defective genes responsible for hereditary diseases (e.g., haemophilia, phenylketonuria, alkaptonuria) with normal genes. This new system of therapy is called gene therapy.
7. Solution of Disputed Parentage:
Disputed cases of parentage can now be solved most accurately by recombinant technology than by blood tests.
The following table shows some medically useful recombinant products and their applications:
8. Diagnosis of Disease:
Recombinant DNA technology has provided a broad range of tools to help physicians in the diagnosis of diseases. Most of these involve the construction of probes: short Segments of single stranded DNA attached to a radioactive or fluorescent marker. Such probes are now used for identification of infectious agents, for instance, food poisoning Salmonella, Pus forming Staphylococcus, hepatitis virus, HIV, etc. By testing the DNA of prospective genetic disorder carrier parents, their genotype can be determined and their chances of producing an afflicted child can be predicted.
9. Production of Transgenic Animals:
Animals which carry foreign genes are called transgenic animals.
Cow, sheep, goat – therapeutic; human proteins in their milk. Fish like common carp, cat fish, salmon and gold fish contain human growth hormone (hGH).
III. Industrial Applications:
In industries, recombinant DNA technique will help in the production of chemical compounds of commercial importance, improvement of existing fermentation processes and production of proteins from wastes. This can be achieved by developing more efficient strains of microorganisms. Specially developed microorganisms may be used even to clean up the pollutants. Thus, biotechnology, especially recombinant DNA technology has many useful applications in crop improvement, medicines and industry.