Applications of Recombinant DNA Technology in Class 12 Biotechnology

Production of Human Insulin Using Recombinant DNA Technology

One of the most important applications of recombinant DNA technology is the production of human insulin, which is vital for treating diabetes mellitus. Earlier, insulin was extracted from animal pancreases, causing allergic reactions and supply issues.

The recombinant DNA method involves:

• Isolating the human insulin gene.
• Inserting this gene into a plasmid vector.
• Introducing the recombinant plasmid into Escherichia coli bacteria.
• Culturing bacteria to produce human insulin protein.
• Harvesting and purifying insulin for medical use.

This process produces insulin identical to natural human insulin, branded as 'Humulin', which ensures a safe, consistent, and large-scale supply. This advancement has greatly improved diabetes management since the 1980s.

Flowchart:

`` Human insulin gene → Plasmid vector insertion → Transformation into E. coli → Bacterial expression → Insulin purification ``

This example highlights how recombinant DNA technology directly benefits human health.

Genetically Modified (GM) Plants and Their Benefits

Recombinant DNA technology is widely used to develop genetically modified plants with improved traits. These transgenic plants contain foreign genes introduced to enhance characteristics such as pest resistance, herbicide tolerance, and increased nutritional value.

Steps to develop transgenic plants:

1. Identify and isolate the desired gene. 2. Insert the gene into a suitable vector, commonly the Ti plasmid from Agrobacterium tumefaciens. 3. Transfer the vector into plant cells using indirect methods (Agrobacterium-mediated transformation) or direct methods (gene gun, electroporation). 4. Regenerate whole plants from transformed cells.

Advantages of GM plants:

• Reduced pesticide use due to pest-resistant traits.
• Higher crop yield and quality.
• Herbicide-tolerant plants simplify weed control.
• Enhanced nutritional content (e.g., Golden Rice enriched with Vitamin A).

GM plants contribute significantly to sustainable agriculture and food security.

Methods of Gene Transfer in Plants

Introducing foreign genes into plant cells can be achieved by two main methods:

1. Direct Gene Transfer:

• Foreign DNA is directly introduced into plant cells without vectors.
• Techniques include gene gun (biolistics) and electroporation.
• Suitable for both monocots and dicots but often less efficient.

2. Indirect Gene Transfer:

• Uses a vector, usually Agrobacterium tumefaciens, to transfer genes.
• The bacterium naturally inserts its Ti plasmid DNA into plant genomes.
• Highly efficient for dicot plants.

Understanding these methods helps Class 12 students grasp how recombinant DNA technology is applied in plant biotechnology.

Molecular Pharming and Transgenic Animals

Molecular pharming is the use of genetically modified plants or animals to produce pharmaceutical substances such as vaccines, antibodies, and hormones.

Applications in transgenic animals include:

• Producing human proteins like clotting factors and growth hormones in milk.
• Generating antibodies for disease treatment.
• Developing animal models for studying human diseases.

For example, transgenic goats have been engineered to produce antithrombin, a blood anticoagulant, in their milk. This method offers a cost-effective and scalable way to produce complex pharmaceuticals.

Molecular pharming combines recombinant DNA technology with animal biotechnology to meet medical needs efficiently.

DNA Fingerprinting and Its Role in Forensics

DNA fingerprinting is a technique that identifies individuals based on unique DNA patterns. It uses recombinant DNA technology to analyze genetic variations.

Process using RFLP (Restriction Fragment Length Polymorphism):

• DNA is cut into fragments by restriction enzymes.
• Fragments are separated by gel electrophoresis.
• The pattern of fragments is unique for each individual.

Applications include:

• Forensic identification of criminals.
• Paternity testing.
• Genetic diversity studies.

This technique highlights the practical use of recombinant DNA technology beyond medicine and agriculture, extending into legal and social fields.