Biotechnology: Notes for UPSC & SSC

What biotechnology means

Biotechnology is the use of living organisms, cells or their enzymes to make useful products. The old forms are thousands of years old — curd, bread, idli and alcohol all depend on microbes. Modern biotechnology changes the DNA itself (genetic engineering) to give an organism a new trait.

DNA in one paragraph

DNA is a double helix — two strands twisted around each other, a model given by James Watson and Francis Crick in 1953 using X-ray images taken by Rosalind Franklin. The strands are held by base pairs: adenine with thymine, guanine with cytosine. A gene is a stretch of DNA that carries the code for a protein. Har Gobind Khorana shared the 1968 Nobel Prize for work on cracking this genetic code.

The recombinant DNA toolkit

Medicines from engineered microbes

• Human insulin made by bacteria was the first recombinant DNA medicine approved for use (1982). Earlier, diabetics used insulin from cattle and pig pancreas.
• Recombinant hepatitis B vaccine is made in yeast.
• Interferons, human growth hormone and blood-clotting factors are also made this way.
• Gene therapy corrects a faulty gene by inserting a working copy; the first clinical use (1990) treated ADA deficiency, an immune disorder.
• Monoclonal antibodies are identical antibodies made in the lab to target one molecule — used in cancer treatment and in diagnostic kits.

GM crops

Regulation in India: the Genetic Engineering Appraisal Committee (GEAC), under the Ministry of Environment, Forest and Climate Change, appraises proposals for large-scale use and environmental release of GM organisms. The legal basis is the 1989 rules framed under the Environment (Protection) Act, 1986. The Department of Biotechnology (DBT), set up in 1986 under the Ministry of Science and Technology, funds and promotes biotech research.

Cloning and stem cells

• Dolly the sheep (born 1996, Roslin Institute, Scotland) was the first mammal cloned from an adult body (somatic) cell, by somatic cell nuclear transfer.
• Stem cells are unspecialised cells that can turn into many cell types. Embryonic stem cells are pluripotent; adult stem cells (bone marrow, cord blood) are more limited.
• Cord-blood banking stores stem cells from the umbilical cord at birth for possible future treatment.

Gene editing: CRISPR-Cas9

CRISPR-Cas9 lets scientists cut DNA at an exact spot and change it. It is borrowed from bacteria, which keep fragments of viral DNA and use the Cas9 enzyme to chop matching DNA when the virus returns. Emmanuelle Charpentier and Jennifer Doudna won the 2020 Nobel Prize in Chemistry for it. It is cheaper and more precise than older methods, but editing human embryos raises serious ethical questions.

DNA fingerprinting and genomes

• DNA fingerprinting compares repetitive DNA regions (VNTRs) that differ from person to person. Developed by Alec Jeffreys (UK, 1984); in India pioneered by Lalji Singh at the Centre for Cellular and Molecular Biology (CCMB), Hyderabad.
• Uses: crime investigation, paternity disputes, identifying disaster victims, and tracking wildlife trade.
• The Human Genome Project (1990–2003) read the roughly 3 billion base pairs of human DNA; humans have only about 20,000 protein-coding genes.

Environment and agriculture

• Bioremediation: using microbes to clean pollution, e.g. oil-eating bacteria. Ananda Mohan Chakrabarty's engineered oil-degrading Pseudomonas became the first genetically engineered organism to be patented, after a 1980 US Supreme Court ruling.
• Biofertilisers: Rhizobium, Azotobacter, blue-green algae and mycorrhiza enrich the soil naturally.
• Biopesticides: Bt sprays and the fungus Trichoderma control pests and diseases without harsh chemicals.
• Biopiracy: patenting traditional knowledge without consent. India successfully challenged patents on turmeric (wound healing) and neem.