Biotechnology & Genetic Engineering

Biotechnology & Genetic Engineering — Complete Study Guide

Introduction to Biotechnology

• Red Biotechnology: Medical applications (vaccines, antibiotics, regenerative medicine).
• Green Biotechnology: Agricultural applications (GM crops, bio-fertilizers).
• White Biotechnology: Industrial applications (industrial enzymes, biofuels).
• Blue Biotechnology: Marine and aquatic environments.
• Yellow Biotechnology: Food production (fermentation, cheese making).

1. Recombinant DNA Technology (Genetic Engineering)

1. Isolation: Extract the desired gene (e.g., human insulin gene) from the donor organism.
2. Cutting: Use Restriction Enzymes (called "molecular scissors") to cut the DNA at specific sequences.
3. Ligation: Use DNA Ligase (called "molecular glue") to paste the gene into a vector (usually a bacterial plasmid).
4. Transformation: Insert the recombinant plasmid back into a host bacterium (E. coli).
5. Cloning & Expression: The bacteria multiply rapidly, producing the desired protein (e.g., mass-producing insulin).

2. CRISPR-Cas9: The Gene Editing Revolution

• How it works: It acts like a highly precise "find and replace" tool in a computer. The guide RNA finds the specific DNA sequence, and the Cas9 enzyme acts as molecular scissors to snip the DNA. The cell then naturally repairs the cut, incorporating the desired changes.
• Applications: Curing genetic diseases (Sickle Cell Anemia), creating drought-resistant crops, potentially eradicating malaria via "gene drives".

3. Genetically Modified Organisms (GMOs) in Agriculture

• A gene from the soil bacterium Bacillus thuringiensis (Bt) is inserted into cotton.
• This gene produces a protein toxic to the bollworm pest, but safe for humans and animals. This dramatically reduces pesticide use.
• Approving Authority in India: GEAC (Genetic Engineering Appraisal Committee) under the Ministry of Environment, Forest and Climate Change.

• Dhara Mustard Hybrid-11. Developed by Delhi University.
• It is a genetically modified, herbicide-tolerant mustard designed to facilitate cross-pollination and increase yields. (Currently facing regulatory hurdles).

• Genetically modified rice containing beta-carotene, leading to a golden color.
• Body converts beta-carotene into Vitamin A. Created to fight Vitamin A deficiency (blindness) in developing countries.

4. Advanced Medical Biotechnology

• Live-Attenuated Vaccines: Weakened pathogen (Measles, Mumps, Rubella).
• Inactivated Vaccines: Killed pathogen (Polio IPV, Covaxin).
• Viral Vector Vaccines: Uses a harmless virus to deliver genetic instructions to cells (Covishield, Sputnik V).
• mRNA Vaccines: The newest tech. Sends mRNA into cells instructing them to make a specific viral protein (spike protein), triggering an immune response, but contains no actual virus (Pfizer, Moderna).

• Stem cells are "blank cells" that have the potential to develop into many different types of cells in the body.
• Totipotent: Can form entire organism (Zygote).
• Pluripotent (Embryonic Stem Cells): Can become almost any cell type.
• Multipotent (Adult Stem Cells): Can become a limited number of cell types (e.g., bone marrow stem cells forming blood cells).
• Application: Regenerative medicine — repairing damaged heart muscle, treating leukemia (bone marrow transplant), spinal cord injuries.

• Treating diseases by replacing, modifying, or repairing a patient's faulty genes rather than using drugs or surgery.
• Example: Treating Severe Combined Immunodeficiency (SCID), often called "Bubble Boy Disease".

5. DNA Fingerprinting

• Developed by Sir Alec Jeffreys in 1984.
• A technique used to identify individuals based on their unique DNA profile. 99.9% of human DNA is identical. DNA fingerprinting looks at the 0.1% that differs — specifically, repetitive sequences called VNTRs (Variable Number Tandem Repeats).
• Applications: Forensic science (identifying suspects), establishing paternity, identifying disaster victims.

6. Cloning (Somatic Cell Nuclear Transfer)

• Producing genetically identical individuals.
• Dolly the Sheep (1996): The first mammal cloned from an adult somatic cell (udder cell) by Ian Wilmut in Scotland.
• Process: Nucleus of an adult cell is transferred into an unfertilized egg cell that has had its nucleus removed. The egg is stimulated to divide and implanted into a surrogate mother.
• Garima: India's first cloned buffalo calf (NDRI, Karnal).