Biotechnology and its Applications

A Genetically Modified Organism, or GMO, is any plant, bacterium, or animal whose genetic material has been altered using recombinant DNA technology. A prominent example is Bt cotton. In this plant, a gene from the bacterium Bacillus thuringiensis is introduced, which allows the plant to produce a protein toxic to insect pests like bollworms. This provides the crop with its own protection, reducing the need for chemical pesticides.

RNA interference (RNAi) is a natural cellular defence mechanism in all eukaryotic organisms. In biotechnology, it is harnessed to protect plants like tobacco from pests such as the nematode Meloidegyne incognita. This is done by introducing a gene into the plant that produces a specific double-stranded RNA (dsRNA). When the nematode feeds on the plant, it ingests this dsRNA, which silences a vital gene in the pest, leading to its death and protecting the host plant from infestation.

Producing human insulin, or 'humulin', using biotechnology was a major breakthrough because it solved the problems associated with insulin extracted from slaughtered cattle and pigs. Animal-derived insulin often caused allergic reactions in patients. Genetically engineered insulin, produced using E. coli bacteria, is structurally identical to human insulin, eliminating immune responses. This method also allows for the production of vast, sterile quantities to meet the global demand for managing diabetes.

Gene therapy is a collection of methods that allows for the correction of a defective gene that causes a disease. It typically involves inserting a normal, functional gene into a patient's cells. The first clinical case of gene therapy was for a patient with adenosine deaminase (ADA) deficiency, an immune disorder. In this treatment, lymphocytes were taken from the patient, a functional ADA gene was introduced into them using a retroviral vector, and these genetically engineered cells were then returned to the patient's body to restore immune function.

The principle of ELISA (Enzyme-Linked Immunosorbent Assay) is the highly specific binding interaction between an antigen and an antibody. Its primary application is to detect the presence of a pathogen (by identifying its antigens) or the antibodies produced by the body in response to that pathogen. If the target molecule is present in a patient's sample, it will bind to the corresponding antibody or antigen in the test kit, and an enzyme-linked reaction will produce a detectable colour change, indicating a positive result.

Transgenic animals are animals whose DNA has been manipulated to carry and express an extra, or foreign, gene. They are created for various purposes, such as:

• To study diseases: By inserting genes that make them susceptible to human diseases, scientists can better understand disease progression.
• To produce biological products: For example, the transgenic cow 'Rosie' was created to produce human protein-enriched milk.
• For vaccine and drug safety testing: To test the safety and efficacy of new vaccines and chemical substances before human trials.

The key ethical issues in biotechnology involve concerns over the manipulation of living organisms and the potential for unintended consequences. Major issues include biopiracy (the unethical patenting and commercialisation of indigenous bioresources) and the potential ecological impact of GMOs. In India, these activities are regulated by the Genetic Engineering Appraisal Committee (GEAC). The GEAC's role is to evaluate the safety of GM research and decide on the validity of introducing GM organisms for public use.

While both are examples of GMOs, their objectives are different. The primary goal of Bt cotton is crop protection. It is genetically engineered to resist pests, thereby increasing crop yield by preventing losses. In contrast, the primary goal of Golden Rice is biofortification or nutritional enhancement. It is modified to produce beta-carotene, a precursor to Vitamin A, to combat malnutrition and deficiency-related diseases in populations that rely on rice as a staple food.

Agrobacterium tumefaciens is considered a natural genetic engineer because it has the innate ability to transfer a piece of its DNA, known as the 'T-DNA', into the genome of the plants it infects. This T-DNA is located on its Ti plasmid. In nature, this process induces tumours (crown galls) in the plant. Biotechnologists have exploited this mechanism by removing the tumour-inducing genes from the Ti plasmid and inserting a desired gene in its place, using the modified plasmid as an effective vector to introduce new traits into plants.