- Transgenic animals are those whose genome is altered by introducing genes from another species.
- They are produced by methods such as DNA microinjection, retrovirus-mediated transfer, and embryonic stem cell transfer.
- Transgenic animals help in studying gene function, regulation, and normal growth and development.
- They are used as disease models to understand disorders like cancer and Alzheimer’s and to develop medicines and vaccines.
- Transgenic animals produce biological products (e.g., human proteins in milk) and are used for vaccine and chemical safety testing.
Definitions [7]
Define.
Biotechnology
The technique of bringing about improvements in living organisms by genetic modifications and hybridization, for the welfare of human beings is known as ‘Biotechnology’.
Definition: Transgenic Animal
A transgenic animal is an animal whose genome has been artificially modified to contain one or more genes from another species.
Definition: Somatic Hybridisation
The process of fusion of protoplasts from two different plant varieties to form a hybrid plant is called somatic hybridisation.
Definition: Genetically Modified Organisms (GMOs)
Plants, animals or microorganisms whose genetic material has been altered by human intervention are called genetically modified organisms (GMOs).
Definition: Tissue Culture
The technique of growing whole plants from a small piece of plant tissue under sterile conditions on a nutrient medium is called tissue culture.
Definition: Totipotency
The ability of a single plant cell or explant to regenerate into a complete plant is called totipotency.
Definition: Micropropagation
The method of producing a large number of plants in a short time using tissue culture techniques is called micropropagation.
Key Points
Key Points: Biotechnology
- Biotechnology involves the use of biological systems, cells, and biomolecules along with genetic and non-genetic techniques for human welfare.
- It integrates sciences such as cytology, biochemistry, molecular biology, and genetic engineering and has major applications in agriculture and pharmacy.
- Biotechnology enables production of antibiotics, vaccines, hormones (insulin), antibodies, and development of high-yield crop varieties through tissue culture and gene manipulation.
- Major benefits include increased crop yield, development of disease- and stress-resistant varieties, and reduced expenditure on disease control.
- In India, biotechnology is promoted by the Department of Biotechnology (DBT) established in 1986, under which several national research institutes function.
Key Points: Transgenic Animal
Key Points: Bt Cotton
- Bacillus thuringiensis produces insecticidal crystal (Bt) proteins that kill specific insect pests like bollworms, beetles, flies and mosquitoes.
- Bt toxin is produced as an inactive protoxin in bacteria and becomes active only in the alkaline gut of insects, where it damages midgut cells and causes insect death.
- Bt toxin genes (cry genes) are transferred into crop plants like cotton to provide inbuilt resistance against insect pests.
- Different cry genes target different insects, e.g., cryIAc and cryIIAb control cotton bollworms, while cryIAb controls corn borer.
Key Points: Pest Resistant Plants
- The root-knot nematode Meloidogyne incognitia infects plant roots and reduces crop yield, especially in tobacco.
- RNA interference (RNAi) is a natural defence mechanism in eukaryotes where a complementary double-stranded RNA (dsRNA) silences specific mRNA and prevents protein synthesis.
- By introducing nematode-specific genes using Agrobacterium, plants produce dsRNA that triggers RNAi, silences nematode genes, and protects the transgenic plant from infestation.
Key Points: Gene Therapy
- Gene therapy is used to treat hereditary diseases by inserting a normal gene into a patient’s cells.
- The inserted gene compensates for a defective or non-functional gene.
- It was first successfully used in 1990 to treat ADA deficiency in a child.
- Early embryonic gene transfer can provide a permanent cure.
Key Points: Molecular Diagnosis
- Molecular diagnosis allows early detection of diseases before symptoms appear.
- PCR detects very small amounts of pathogen DNA/RNA by amplification (used for HIV, cancer mutations).
- DNA/RNA probes identify specific mutated genes through hybridisation techniques.
- ELISA detects diseases based on antigen–antibody interaction.
Key Points: Ethical Issues in Biotechnology
- Genetic manipulation of organisms needs ethical regulation due to possible harm and unpredictable ecological effects.
- Genetically Modified (GM) organisms may cause unknown environmental risks when released into ecosystems.
- In India, GEAC (Genetic Engineering Approval Committee) regulates GM research and public use for safety.
- Patent issues arise when companies claim rights over biological resources traditionally used by local communities.
- Biopiracy refers to unauthorised use of bio-resources and traditional knowledge without fair compensation.
- India has strengthened patent laws to protect biodiversity, traditional knowledge, and ensure benefit sharing.
Key Points: Genetically Engineered Insulin
- Earlier, insulin for diabetes treatment was obtained from cattle and pigs, which sometimes caused allergic reactions in humans.
- Human insulin is made of two polypeptide chains (A and B) joined by disulphide bonds and is initially produced as a pro-hormone containing an extra C-peptide.
- The main challenge in recombinant insulin production was assembling the A and B chains into a biologically active form.
- In 1983, human insulin was produced using recombinant DNA technology by inserting genes for A and B chains into E. coli, producing them separately and later joining them to form functional insulin.
Important Questions [8]
- Why a transgenic animals so called?
- "Artificial insemination helps overcome several problems of normal mating in cattle". Do you agree? Support your answer with any three reasons.
- Explain the role of transgenic animals in (i) Vaccine safety and (ii) Biological products with the help of an example each.
- How have transgenic animals proved to be beneficial in production of biological products?
- How have transgenic animals proved to be beneficial in chemical safety testing?
- GEAC stands for ______.
- Why Has the Indian Government Set up the Organisation Named Geac ? Give Any Two Reasons.
- What is biopiracy?
