Modern biotechnology began with the development of recombinant DNA technology in 1973 (Cohen and Boyer). This allowed precise manipulation of genes across species, launching the genetic engineering era and the modern biotech industry.

Transgenic animals are used for: pharming (producing therapeutic proteins like factor IX, alpha-1-antitrypsin in milk), disease models (humanised mice for cancer, Alzheimer's research), drug testing, and xenotransplantation research.

Ex vivo gene therapy removes cells from the patient, genetically modifies them in the laboratory (correcting the defect), and returns them to the patient. This approach allows quality control before reinfusion. ADA-SCID gene therapy uses this approach.

Major concerns about GMO crops include: potential gene flow/outcrossing to wild relatives (creating herbicide-resistant weeds), effects on non-target organisms, reduced biodiversity, corporate control of food supply, and unknown long-term health and environmental effects.

The Flavr Savr tomato was engineered with an antisense copy of the polygalacturonase gene to reduce cell wall softening. This delayed fruit softening and rotting after harvest, extending shelf life — but it was commercially unsuccessful and withdrawn.

Antisense technology uses short antisense RNA (complementary to target mRNA) to block translation by binding to the mRNA and preventing ribosome access. It can selectively suppress expression of specific genes — used in research and therapeutics.

Bioethanol is a biofuel produced by microbial fermentation of plant sugars (from sugarcane, corn, cellulose). It is a renewable, cleaner-burning alternative to fossil fuels. Yeast and some bacteria convert sugars to ethanol by fermentation.

Proteomics is the large-scale study of the proteome — the entire set of proteins expressed by a cell, tissue, or organism at a given time. It includes protein identification, quantification, interactions, and functional characterisation.

Genomics is the study of complete genomes — all the genetic information of an organism. It includes genome sequencing, gene mapping, structural genomics, functional genomics (how genes work), and comparative genomics (comparing genomes across species).

The term 'biotechnology' was coined by the Hungarian agricultural engineer Karl Ereky in 1919. He used it to describe the use of living organisms to produce useful products — originally referring to large-scale pig farming.

Haemophilus influenzae (a bacterium) was the first organism to have its complete genome sequenced, in 1995 by the Institute for Genomic Research (TIGR). This was followed by many other organisms including yeast (1996) and C. elegans (1998).

DNA fingerprinting (DNA profiling) was developed by Sir Alec Jeffreys at the University of Leicester in 1984. He discovered minisatellite regions in human DNA that are highly variable between individuals, creating a unique 'fingerprint'.

Biotechnology in agriculture includes: herbicide-resistant crops (Roundup Ready), pest-resistant crops (Bt crops), improved nutrition (Golden Rice), drought tolerance, and faster ripening. All three represent major areas of crop biotechnology.

Stem cells are used therapeutically to repair and replace damaged tissues (bone marrow transplants, retinal repair), in vaccine production (virus propagation), in diagnostic models, and as research tools for understanding disease mechanisms.

Monoclonal antibodies are produced by hybridoma cells — formed by fusing a specific antibody-producing B lymphocyte with a myeloma (cancer) cell. The hybridoma cell immortally produces identical (monoclonal) antibodies of a specific type.

Penicillin was the first antibiotic discovered by Alexander Fleming in 1928 when he noticed that the mould Penicillium notatum inhibited bacterial growth. It was developed as a therapeutic antibiotic by Florey and Chain in the 1940s.

Fermentation (both aerobic and anaerobic microbial processes) is used to produce antibiotics (penicillin from Penicillium), alcohol (ethanol from yeast fermentation of sugars), yoghurt (lactic acid from Lactobacillus), and many other products.

Cell culture involves separating individual cells from tissue and growing them in a nutrient medium (containing salts, glucose, amino acids, vitamins, growth factors, and serum) under controlled conditions. It is used in vaccine production, drug testing, and research.

A GMO (Genetically Modified Organism) is an organism whose genome has been artificially altered using recombinant DNA technology — introducing, removing, or modifying specific genes. Examples include Bt cotton, herbicide-resistant crops, and transgenic animals.

The term here describes the property of totipotency — the ability of a dedifferentiated plant cell to regenerate a complete plant. Dedifferentiation is the process of reverting from a specialised state back to a meristematic (undifferentiated) state.

CRISPR-Cas9 is a revolutionary gene editing tool that uses a guide RNA to direct the Cas9 nuclease to cut DNA at a specific location. It enables precise, efficient, and cheap editing of genomes in virtually any organism — a transformative technology.

Micropropagation is the commercial application of plant tissue culture to rapidly produce thousands or millions of genetically identical plants (clones) from a small explant in a sterile, controlled environment — used for orchids, potatoes, bananas.

RNA interference (RNAi) is a mechanism that silences specific gene expression using double-stranded RNA (dsRNA). Small interfering RNAs (siRNAs) guide the RISC complex to degrade target mRNA. RNAi is used in research, agriculture (Bt crops), and therapeutics.

Embryonic stem cells (from the inner cell mass of blastocyst) are pluripotent — they can differentiate into any cell type of the body but cannot form the placenta or trophoblast. Totipotent cells (zygote, early blastomeres) can form a complete organism.

Bioinformatics applies computer science, mathematics, and statistics to analyse biological data — especially DNA/protein sequences, genomic data, and molecular structures. It is essential for processing the vast data from genome sequencing projects.

The Flavr Savr tomato was the first genetically modified food approved for human consumption by the FDA in 1994. It was engineered with an antisense gene to delay softening and extend shelf life — though it was later withdrawn from market.

SCNT is the technique used in reproductive cloning — the nucleus of a somatic (body) cell is transferred into an enucleated egg. The reconstructed egg is stimulated to divide and develop into a clone of the nuclear donor (as in Dolly).

Recombinant vaccines are produced by cloning the gene encoding a specific antigen (e.g., hepatitis B surface antigen) and expressing it in a host (yeast, bacteria). The purified protein is used as vaccine — safer than whole-pathogen vaccines.

Anther culture (androgenesis) involves growing immature anthers containing pollen (microspores) on culture medium to produce haploid plants. These haploid plants can be converted to diploid by colchicine treatment, creating homozygous lines.

Plant tissue culture media contain: mineral salts (macro and micronutrients), vitamins (thiamine, niacin), plant hormones (auxin and cytokinin in specific ratios to control growth), sugar (carbon source), and agar (solidifying agent).

Protoplast fusion (removal of cell walls then fusing the protoplasts) is used to produce somatic hybrids — cells combining the genomes of two different species. The classic example is the 'pomato' (potato-tomato hybrid) produced this way.

Totipotency is the ability of a single cell to develop into a complete, mature organism with all its cell types. Fertilised eggs (zygotes) are totipotent. Plant cells retain totipotency throughout life — enabling tissue culture propagation.

RFLP (Restriction Fragment Length Polymorphism) analysis is used in DNA fingerprinting — different individuals have different restriction fragment patterns due to variations in DNA sequences. It is used in forensics, paternity testing, and disease gene mapping.

A cDNA library contains cDNA sequences (synthesised from mRNA using reverse transcriptase) representing all genes actively expressed in a tissue at a given time. It differs from a genomic library which contains all DNA including non-coding regions.

Reverse transcriptase (found in retroviruses like HIV) synthesises complementary DNA (cDNA) from an mRNA template. cDNA lacks introns and represents the coding sequence only — it is used to clone eukaryotic genes in bacterial systems.

The first approved human gene therapy trial was conducted in 1990 at the NIH — treating a 4-year-old girl with ADA-SCID (adenosine deaminase deficiency causing severe combined immunodeficiency). Functional ADA genes were delivered via a retroviral vector.

Gene therapy introduces functional copies of defective or missing genes into a patient's cells to treat or cure genetic diseases. Both ex vivo (cells removed, modified, reintroduced) and in vivo (vector delivered directly) approaches are used.

ELISA (Enzyme-Linked Immunosorbent Assay) is a diagnostic technique that uses antibodies and enzyme-linked detection to identify and quantify specific proteins (antigens or antibodies) in a sample — used for HIV testing, pregnancy tests, and more.

Southern blotting (Edwin Southern, 1975) is used to detect specific DNA sequences — DNA fragments separated by gel electrophoresis are transferred to a membrane and probed with labelled complementary DNA. Northern is for RNA; Western is for protein.

Dolly (1996, Roslin Institute, Scotland) was the first mammal cloned from an adult somatic cell — a mammary gland cell using somatic cell nuclear transfer (SCNT). She proved that adult differentiated cells retain totipotency.

Biotechnology is the application of biological systems and living organisms (or their products) to develop products and processes for human benefit — including medicine, agriculture, food production, and environmental management.

Sticky ends (cohesive ends) are short single-stranded overhangs produced when certain restriction enzymes (like EcoRI) make staggered cuts in the two strands of DNA. These complementary overhangs allow efficient joining of DNA fragments.

An ideal cloning vector must have: an origin of replication (to replicate independently in host), a selectable marker (e.g., antibiotic resistance to identify transformed cells), and restriction enzyme sites (to insert foreign DNA).

Gene cloning involves inserting a gene of interest into a vector (plasmid), transforming bacteria with the recombinant vector, and growing the bacteria. As bacteria multiply, they produce millions of identical copies of the inserted gene.

Bt toxin (Cry protein) is a crystalline protein produced by the soil bacterium Bacillus thuringiensis. It is toxic to specific insect larvae (lepidoptera, coleoptera) but harmless to humans and other animals. It is used in Bt crops and biopesticides.

A transgenic organism contains a gene (transgene) that has been artificially introduced from another organism — either the same or a different species. Examples include Bt cotton, Golden Rice, and transgenic mice for medical research.

The Human Genome Project was officially completed in April 2003, but a working draft covering 90% of the genome was announced in June 2000. It took 13 years and cost approximately $3 billion to sequence all 3 billion base pairs.

DNA sequencing determines the exact order of nucleotide bases (A, T, G, C) in a DNA molecule. The Sanger (dideoxy chain termination) method was the first widely used technique; next-generation sequencing (NGS) is now standard.

Bioremediation is the use of microorganisms (bacteria, fungi, algae) to degrade or detoxify environmental pollutants (oil spills, heavy metals, pesticides) in soil and water, converting them to less harmful or non-toxic compounds.

Transformation is the uptake of foreign DNA (including recombinant DNA) by bacterial cells. In genetic engineering, bacteria are made chemically competent (using CaCl₂) or electroporated to take up plasmid vectors.

Gel electrophoresis separates DNA fragments by size — smaller fragments migrate faster through the agarose gel matrix toward the positive electrode. The gel is stained with ethidium bromide or SYBR Green to visualise DNA bands.

PCR stands for Polymerase Chain Reaction. It was invented by Kary Mullis in 1983 (Nobel Prize 1993). It uses repeated cycles of denaturation, annealing of primers, and extension by DNA polymerase to amplify specific DNA sequences.

PCR (Polymerase Chain Reaction) is a technique that exponentially amplifies a specific DNA sequence using primers (short complementary sequences) and thermostable DNA polymerase (Taq polymerase). It can produce millions of copies from a single DNA molecule.

Golden Rice is a GM variety of rice engineered to produce beta-carotene (precursor to Vitamin A) in the endosperm. It was developed to address Vitamin A deficiency, a major cause of blindness in developing countries.

Human insulin was first produced by cloning the insulin gene in E. coli in 1978 by Genentech scientists (Herbert Boyer and team). It was approved by the FDA in 1982 as the first recombinant DNA pharmaceutical product.

The first transgenic plants were produced in 1983 when scientists introduced foreign genes into tobacco and petunia using Agrobacterium Ti plasmid. This marked the beginning of plant genetic engineering.

The Ti (tumour-inducing) plasmid of Agrobacterium tumefaciens is the most commonly used vector to introduce foreign genes into plant cells. The T-DNA region integrates into the plant genome, carrying the gene of interest.

Escherichia coli (E. coli) is the most widely used host organism in recombinant DNA technology because it grows rapidly, is well-characterised genetically, is easy to transform, and can produce large amounts of foreign proteins.

A transgene is a gene from one organism that has been introduced (transferred) into the genome of another organism. The resulting organism is called transgenic. Transgenes are used to produce valuable proteins and create disease models.

DNA ligase joins DNA fragments by forming phosphodiester bonds between the 3'-OH and 5'-phosphate ends of adjacent DNA strands. It is essential for sealing nicks in DNA and joining insert DNA to vector in cloning.

A palindromic DNA sequence reads the same in the 5'→3' direction on both strands. For example, EcoRI recognises 5'-GAATTC-3' on one strand and 5'-GAATTC-3' on the complementary strand (reading 5'→3').

Restriction endonucleases (restriction enzymes) are bacterial enzymes that recognise specific short palindromic DNA sequences (4-8 bp) and cut both strands. They protect bacteria from foreign DNA and are essential tools in genetic engineering.

Molecular cloning is the production of millions of identical copies of a specific DNA fragment or gene by inserting it into a vector and growing it in a host organism. It allows amplification and study of specific genes.

Genetic engineering (recombinant DNA technology) is the deliberate manipulation of an organism's genome to introduce, remove, or modify specific genes — transferring DNA between different organisms to produce desired traits.

Recombinant DNA technology was first developed in 1973 by Stanley Cohen and Herbert Boyer. They demonstrated that DNA from two different organisms (E. coli and Staphylococcus) could be joined and expressed in bacteria.

When a gene of interest is inserted into a cloning vector (plasmid, phage), the resulting construct is called recombinant DNA. The vector carrying the foreign gene is introduced into a host organism for cloning and expression.

Cybridization (cytoplast hybridisation) occurs when a cytoplast (enucleated cell) fuses with a whole cell of another species. Protoplast fusion refers to fusion of cells with nuclei. Somatic hybridisation is the broader term.

Friable callus is a loose, crumbly type of plant callus that easily breaks apart into individual cells or small cell clusters. It is ideal for producing suspension cultures and for protoplast isolation.

A synkaryocyte (synkaryon) is formed when the two nuclei in a heterokaryon (a cell with two genetically different nuclei) fuse to produce a single hybrid nucleus. This is an important step in somatic cell hybridisation.

Differentiation is the process by which undifferentiated meristematic cells become specialised into specific cell types (xylem, phloem, muscle, nerve cells). Gene expression is selectively activated during differentiation.

Maleness in humans is determined by the SRY gene on the Y chromosome — it is Y-linked. The presence of a Y chromosome (specifically the SRY gene) initiates testis development and male sex determination.