Biotechnology and Genetic Engineering

1 Introduction to Biotechnology – Definition, History and Major Milestones

The story of human insulin illustrates what biotechnology really is—the use of living organisms, their cells, or their parts (such as enzymes, proteins) to develop products or processes that are useful to human life. According to the European Federation of Biotechnology, "Biotechnology is the integrated use of microorganisms, cell and tissue culture techniques, and the engineering and technological applications of biological processes to fully utilize the potential of science in the production of goods and services." Simply put—biotechnology is the art and science of controlling the biological capabilities that nature has endowed living organisms with (such as fermentation, protein synthesis, nitrogen fixation) for human well-being.

Major milestones in history

Major Branches of Biotechnology (Color-Based Classification)

• Red Biotechnology: Medical and health sector – vaccines, antibiotics, gene therapy.
• Green Biotechnology: Agriculture sector – Bt crops, biofertilizers, disease-resistant plants.
• White Biotechnology: Industrial areas—enzymes, biofuels, biodegradable plastics.
• Blue Biotechnology: Obtaining new compounds and medicines from marine organisms.

2 Gene cloning and gene banks

The word 'clone' is derived from the Greek word 'klon' meaning 'twig' or 'branch' – a new branch growing from the parent plant, exactly like the original. In biology, a clone refers to an offspring that is genetically identical to its parent. Gene cloning involves creating multiple exact copies of a particular gene (a piece of DNA) in a laboratory, so that that gene can be studied or transferred to another organism to create a useful product. Remember – gene cloning and 'organism cloning' (such as Dolly the sheep) are two different things.

Gene Bank

A gene bank is a facility where seeds, tissue, DNA, or genetic material from various organisms (mainly plant varieties and wild relatives) are preserved for long periods at extremely low temperatures (usually -18°C or below) for future use in biodiversity conservation, breeding programs, and food security. It is a form of 'genetic insurance'—a crop variety's genetic source remains intact even if it becomes extinct due to climate change, disease outbreak, or natural disaster.

• National Bureau of Plant Genetic Resources (NBPGR), New Delhi — India's national gene bank, preserving more than 4.7 lakh plant genetic samples.
• Svalbard Global Seed Vault, Norway — The world's largest 'doomsday' seed repository, located beneath the Arctic ice.
• Rajasthan agricultural universities (such as Swami Keshwanand Rajasthan Agricultural University, Bikaner) also have gene banks for regional crop varieties—such as the community gene bank of native fennel varieties of Sirohi (details in Chapter 15).

📌 महत्वपूर्ण

🖼️ Main steps of gene cloning – selection of gene, cutting with restriction enzyme, insertion into plasmid, transfer into bacterial cell and selection

3 Tools of genetic engineering – restriction enzymes, vectors, DNA ligase

Imagine DNA as a very long strand, with thousands of useful 'words' (genes) linked together. Genetic engineering requires scientists to cut a specific word at the exact spot on this strand, add it to another strand, and then permanently strengthen that link. This requires three main 'tools'—'molecular scissors' (restriction enzymes), a 'vehicle' to deliver the gene to the new cell (vector), and 'molecular glue' (DNA ligase) to make the link permanent.

(A) Restriction enzymes – molecular scissors

Restriction enzymes (Restriction Endonuclease) are specialized enzymes that recognize and cut DNA molecules at a specific, predetermined sequence—much like a sewing machine cuts fabric only along a marked line. They are originally found in bacteria, where they protect the bacteria from virus attack by cutting and destroying the virus's DNA. The most well-known restriction enzymesEcoRIwhich is E. coli (Escherichia coli) is derived from bacteria and recognizes and cuts the DNA sequence GAATTC.

• Sticky Ends: Many restriction enzymes cut DNA in an asymmetric manner, creating single-strand protruding ends—these 'sticky ends' are able to bind to any other DNA fragment if the ends are complementary.
• Blunt Ends: Some enzymes cut DNA completely straight across, leaving no bulge.
• Restriction enzyme nomenclature: The first letter is from the genus, the next two letters are from the species—e.g., in EcoRI, 'E' = Escherichia, 'co' = coli, 'R' = RY13 strain, 'I' = first enzyme discovered.

(B) Vectors

A vector is a 'vehicle' that carries the cut gene (attached to the plasmid) into a host cell (such as a bacterium) and maintains it there stably, allowing it to replicate as the cell divides.

(C) DNA ligase – molecular glue

DNA ligase is an enzyme that permanently joins the ends of cut DNA fragments by forming a phosphodiester bond—much like tying a knot between the two ends of a broken strand. The most commonly used ligasesT4 DNA ligasewhich is derived from T4 bacteriophage.

4 Recombinant DNA Technology – Step-by-Step Process

Recombinant DNA (rDNA) is a DNA molecule created by artificially joining DNA segments from two different sources (such as human and bacterial) in the laboratory—that is, it does not occur naturally in nature, but is instead 'designed' by scientists. Using the three tools (restriction enzymes, vectors, DNA ligase) learned in the previous topic, the entire process occurs in the following well-organized steps.

Detailed description of the steps

• Gene identification and extraction: First, the gene to be cloned (e.g., the human insulin gene) is identified and its pure DNA is extracted from the cell.
• Cutting: Both the desired gene and the carrier plasmid are cut with the same restriction enzyme (such as EcoRI) – this creates identical 'sticky ends' on both sides, which complement each other.
• Insertion: The cut gene fits into the open plasmid – complementary sticky ends form hydrogen bonds.
• Ligation: The DNA ligase enzyme makes this connection permanent by forming a phosphodiester bond—it is now a complete recombinant plasmid.
• Transformation: The recombinant plasmid is introduced into the host bacterial cell—usually by temporarily permeabilizing the cell membrane by calcium chloride treatment or heat-shock methods.
• Selection: Since not all bacterial cells take up the plasmid, only successful cells are allowed to survive in the antibiotic-containing medium using an antibiotic-resistant gene (marker gene) present in the plasmid.
• Cloning and Expression: Selected bacterial cells are cultured on a large scale in large bioreactors, where they produce large quantities of the desired protein (such as insulin).

5 Polymerase Chain Reaction (PCR) and DNA Fingerprinting

In 1983, American scientist Kary Mullis was driving at night when an idea struck him: could a small piece of DNA be replicated repeatedly in a test tube to produce millions of copies, without the help of a living cell? This idea later developed into the Polymerase Chain Reaction (PCR), for which Mullis received the Nobel Prize in Chemistry in 1993. Today, modern biology is unimaginable without PCR—it's used everywhere from COVID-19 testing to crime investigations.

PCR process—three steps repeated over and over again

PCR works like a 'molecular photocopy machine,' doubling a specific segment of DNA in each cycle. A special heat-tolerant enzyme, Taq polymerase, is used, which is obtained from the hot spring bacterium Thermus aquaticus, and is not destroyed even at high temperatures.

• Denaturation (~95°C): The two strands of DNA are separated due to heat.
• Annealing (~50-65°C): Short primers are attached to both ends of the desired segment of DNA.
• Extension (~72°C): The Taq polymerase enzyme starts from the primer and forms a new complementary strand – thus doubling the amount of DNA.

This cycle is repeated 20–35 times—with each cycle doubling the amount of DNA, resulting in millions (2ⁿ) copies of a single fragment in just a few hours.

📌 महत्वपूर्ण

PCR cycles – denaturation, annealing, and extension, doubling the amount of DNA in each cycle

Applications of PCR

• RT-PCR testing (diagnosis) for infectious diseases including COVID-19.
• DNA amplification from even very small amounts (a single hair or drop of blood) in criminal investigations.
• Paternity/Maternity Testing and Genealogical Studies.
• Preparation of sufficient quantity of the desired gene before gene cloning.

DNA Fingerprinting/Profiling

Just as every person's fingerprint is unique, every person's DNA contains regions whose structure (repetition pattern) varies from person to person—these are called VNTRs (Variable Number Tandem Repeats). DNA fingerprinting uses these variations to establish a person's unique identity. This technique was invented in 1984 by British geneticist Alec Jeffreys.

• Process: DNA extraction → shearing with restriction enzymes → separation by size by gel electrophoresis → marking with radioactive/fluorescent probes → obtaining band patterns (e.g. barcodes).
• In gel electrophoresis, DNA fragments move toward a positive electrode due to a negative charge in an electric field—small fragments move faster and larger fragments move slower, forming a characteristic band pattern.

📌 महत्वपूर्ण — 🖼️ DNA fingerprinting

unique band pattern (like a barcode) obtained by gel electrophoresis

6 Medical applications of genetic engineering

Recombinant DNA technology has revolutionized medicine. Proteins and hormones that previously had to be extracted from human or animal tissue with great difficulty, high cost, and the risk of infection can now be produced safely, purified, and in unlimited quantities in the laboratory using bacteria or animal cells.

7 Applications in Agriculture – Bt Crops

A common bacterium found in soil is—Bacillus thuringiensis(Bt for short). This bacterium produces a special type of protein crystal (Cry protein) that destroys certain insects (such as bollworms) after reaching their intestines, but is completely safe for humans and other organisms. Scientists have developed a new method for thiscryThey began transferring the gene into the plant's DNA—causing the plant to produce the insecticidal protein itself. Today's Bt crops are based on this principle.

Bt cotton — India's most widespread GM crop

Bt cotton was commercially approved in India in 2002 and today covers over 95% of the country's total cotton acreage. It carries the cry1Ac and cry2Ab genes, which confer resistance to cotton's biggest enemies—the pink bollworm and the American bollworm. This has significantly reduced pesticide spraying and increased farmer yields and incomes.

• The Genetic Engineering Appraisal Committee (GEAC) is responsible for the approval and regulation of Bt crops in India (detailed discussion in Chapter 11).
• Other Bt crops (at research/trial stage): Bt maize, Bt eggplant (Bt Brinjal — commercial approval suspended in India), Bt tomato, Bt tobacco.

Scientists' concerns about Bt cotton

• Development of Bt-resistance in insects — There have been reports of some bollworm populations developing resistance to the Cry protein with continued use.
• Ecologists are concerned about the potential impact on non-target organisms such as butterflies and friendly insects.
• Refuge Strategy: Planting a 'refuge' of non-Bt crops alongside Bt crops is mandated to slow the development of resistance and maintain susceptible insect populations.

8 Transgenic plants and animals

A transgenic organism is a plant or animal whose DNA has been permanently implanted with one or more genes from another organism (even a completely different species) by artificially transferring them. These newly added genes are called transgenes. One of nature's own genetic engineers—soil bacteria—is used to transfer genes into plants.Agrobacterium tumefaciens।

(A) Transgenic plants – Agrobacterium/Ti plasmid method

Agrobacterium tumefaciensAgrobacterium is a soil bacterium that naturally infects plants and causes a disease (a type of lump/tumor) called 'Crown Gall'. It contains a special plasmid—the Ti plasmid (Tumour-inducing Plasmid)—which naturally transfers a portion of its T-DNA into the plant cell's chromosome. Scientists have exploited this natural ability to remove the pathogenic portion of the Ti plasmid and replace it with a desired gene (such as the Bt gene)—thus Agrobacterium now acts as a 'natural gene carrier', delivering the desired gene into the plant cell on its own.

📌 महत्वपूर्ण

🖼️ Transfer of T-DNA into a plant cell by Agrobacterium tumefaciens – a natural gene-carrying system

(B) Transgenic animals

Gene transfer in animals is more challenging, and two main methods are used: microinjection, in which a very fine needle is used to inject the desired gene directly into the nucleus of a fertilized egg; and retroviral vector method, in which a retrovirus is used as a vector to introduce the gene into the cell.

• Transgenic cows/goats – engineered to produce human-use proteins in their milk, such as transgenic goats producing the neuroprotective protein tPA (useful in the treatment of heart attacks and strokes), from whose milk this protein is purified – this is called 'pharming' (Pharmaceutical + Farming).
• The 'Supermouse' experiment—creating a mouse nearly twice the size of a normal mouse by inserting a human/mouse growth hormone gene into mouse DNA—was a landmark experiment demonstrating the effectiveness of transgenic technology.
• Transgenic fish (such as the fast-growing AquAdvantage salmon) — fish that achieve marketable size in half the normal time by inserting a growth hormone gene.

9 Gene therapy

When a person is born with a defective or missing gene, the resulting disease is impossible to completely cure with conventional medicine—because the problem lies within the body's basic 'software' (DNA). Gene therapy is a cutting-edge medical approach that attempts to correct the effects of the defective gene by inserting a working copy of the healthy gene into the patient's cells—that is, correcting the root cause of the disease (the DNA-level defect) rather than just treating its symptoms.

Gene Therapy Somatic vs. Germline

Major subtypes of gene therapy

A. Ex-vivo gene therapy: The patient's cells (such as bone marrow stem cells) are removed from the body and re-transplanted in the laboratory, inserting a healthy gene using a retroviral vector. Uses: SCID, sickle cell anemia, thalassemia, some blood cancers.

B. In-vivo gene therapy: The healthy gene is injected directly into the affected organ/tissue within the patient's body using an adenovirus vector. Uses: Experimental therapy for some cancers, Alzheimer's disease, and Parkinson's disease.

C. Antisense Therapy: Blocking the expression of a harmful gene—such as its experimental use in the treatment of certain brain tumors (malignant gliomas).

10 Bioremediation and Biopesticides

Bioremediation is a technique that uses the natural ability of microorganisms (bacteria, fungi) or plants to remove or make less toxic harmful pollutants (e.g., oil spills, heavy metals, pesticide residues) from contaminated soil, water, or air—that is, 'using nature to clean up pollution'.

• Mercury-resistant bacteria: Certain specially engineered bacteria absorb toxic mercury from industrial wastewater and convert it into a less-harmful form.
• Oil-spill cleanup: Some bacteria (such as Pseudomonas species) are able to degrade the hydrocarbons of crude oil in marine oil spills.
• Phytoremediation: Some plants absorb heavy metals (such as lead, cadmium) from the soil through their roots and accumulate them, thereby purifying the soil.

11 Industrial Biotechnology – Enzyme, Antibiotic and Vitamin Production

Industrial Biotechnology (White Biotechnology) uses microorganisms and their enzymes to produce industrial products on a large scale—it is considered more energy-efficient and environmentally friendly than traditional chemical processes.

Antibiotic production also involves industrial fermentation of microorganisms (mainly fungi and actinomycetes)—since the discovery of penicillin (1928), more than 6,000 natural antibiotic compounds have been isolated from various microorganisms (see Chapter 8 for details on the technological processes and classification of antibiotics). Similarly, many vitamins, such as vitamin B12 and riboflavin (vitamin B2), are also produced industrially by microbial fermentation, which is cheaper and more pure than chemical synthesis (see Chapter 9 for an in-depth look at fermentation technology).

12 India's Bio-economy and DBT/BIRAC policies

India today ranks among the top 12 biotech economies in the world, and third in the Asia-Pacific region. The Department of Biotechnology (DBT), Government of India, operating under the Ministry of Science and Technology, is the nodal agency for biotechnology research, policy-making, and industrial development in the country.

India's Bio-Economy – Statistics and Targets

Major policies and projects

• Genome India Project: Completed in January 2025—The complete genomes of approximately 10,000 individuals from diverse populations across the country were sequenced, identifying approximately 180 million genetic variants. This is a milestone in understanding the genetic diversity of Indians and developing India-specific precision medicine.
• BioE3 Policy (Biotechnology for Economy, Environment and Employment, August 2024): National policy to promote high-performance biomanufacturing – focused on six priority areas (bio-based chemicals and enzymes, smart proteins and functional foods, precision biomedicine, climate-resilient agriculture, carbon capture and utilization, marine and space biotechnology).
• Bio-RIDE (Biotechnology Research Innovation and Entrepreneurship Development): Scheme to support research, innovation and entrepreneurship with an outlay of approximately ₹9,197 crore.
• BIRAC (Biotechnology Industry Research Assistance Council): A public sector undertaking of DBT, which provides financial assistance, incubation (through BioNEST centres) and technical support to biotech startups and small-medium enterprises.

13 Stem Cell Research and Regulation in India

Stem cells are specialized cells in the body that possess two unique abilities—self-renewal and differentiation into various specialized cells (e.g., nerve cells, blood cells, and heart cells). This dual ability makes stem cells highly promising for repairing damaged tissues, treating degenerative diseases, and regenerative medicine.

Regulation of stem cell research in India

• National Guidelines for Stem Cell Research 2025: Jointly issued by the Indian Council of Medical Research (ICMR) and the Department of Biotechnology (DBT) — sets ethical limits and scientific standards for stem cell research.
• NAC-SCRT (National Apex Committee for Stem Cell Research and Therapy): Registration and approval of all stem cell research proposals in the country mandatorily passes through this committee.
• Central Drugs Standard Control Organisation (CDSCO): CDSCO's permission is mandatory before any stem cell based medical product can be started for human clinical trials.
• Extremely strict ethical protocols apply to research on embryonic stem cells, and the use of human embryos for reproductive cloning is strictly prohibited in India.

14 Biotechnology in Rajasthan

Rajasthan, with its unique agro-climatic conditions (arid and semi-arid regions), is embracing biotechnology as an important tool for developing drought-tolerant crops, water conservation, and rural bioentrepreneurship. The state government has taken several concrete steps in this direction.

Rajasthan Biotechnology Policy 2015 and Biotech Park

Under the Rajasthan Biotechnology Policy 2015, three major biotech parks have been established to promote biotechnology research, industry and startups in the state:

Bt cotton in Rajasthan

Bt cotton cultivation in Rajasthan began in 2005, and today its adoption rate exceeds 95% in the state's cotton-producing regions (primarily the Sri Ganganagar and Hanumangarh regions). From 2005 to 2015, Bt cotton adoption resulted in an increase in farmers' yields by approximately 60%, along with a significant reduction in the need for pesticide spraying—reducing production costs and increasing farmers' net incomes.

• The Department of Biotechnology at Rajasthan Agricultural University (Bikaner) and Maharana Pratap University of Agriculture and Technology (Udaipur) are actively conducting research to develop drought-tolerant and disease-resistant crop varieties.
• Biotechnology based research programmes are also underway in the state for genetic conservation of local animal breeds like camel, goat and sheep (detailed discussion in Chapter 15).