Lesson 12 of 12 · 13 min
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Must-know facts
20 facts
- 01Three research areas: superior catalyst (organism or pure enzyme), optimal conditions for it, downstream processing.
- 02Three routes to more food: agro-chemical, organic, and GM crop-based agriculture; the Green Revolution tripled food supply.
- 03Totipotency: any cell or explant can regenerate a whole plant; micro-propagation gives genetically identical somaclones.
- 04Tissue culture medium: sucrose as carbon source, inorganic salts, vitamins, amino acids, auxins and cytokinins.
- 05Virus-free plants come from the meristem (apical and axillary), which stays free of virus; banana, sugarcane, potato.
- 06Protoplast fusion gives somatic hybrids; tomato + potato gave the pomato, which was not commercially useful.
- 07Golden rice is vitamin A enriched rice.
- 08Bt toxin is an inactive protoxin; the insect's alkaline gut pH solubilises the crystal and activates it; it makes pores in midgut epithelial cells.
- 09Bt proteins act on lepidopterans, coleopterans and dipterans; cryIAc and cryIIAb control cotton bollworms, cryIAb controls corn borer.
- 10RNAi against Meloidogyne incognita in tobacco: Agrobacterium vectors, sense + anti-sense RNA form dsRNA that silences nematode mRNA.
- 11About 30 recombinant therapeutics approved worldwide; 12 marketed in India.
- 12Insulin: chains A and B joined by disulphide bridges; pro-insulin carries a C peptide removed at maturation.
- 131983, Eli Lilly: A and B chain DNA put in E. coli plasmids, chains made separately and joined by disulphide bonds.
- 14First clinical gene therapy: 1990, a 4-year-old girl with ADA deficiency; lymphocytes + ADA cDNA via retroviral vector; periodic infusion needed.
- 15PCR detects pathogens at very low concentration and is routine for HIV; radioactive probes + autoradiography; ELISA uses antigen-antibody interaction.
- 16Over 95 per cent of transgenic animals are mice.
- 17Rosie (1997), the first transgenic cow: milk with human alpha-lactalbumin, 2.4 grams per litre.
- 18Human α-1-antitrypsin from transgenic animals treats emphysema; transgenic mice test polio vaccine safety.
- 19GEAC = Genetic Engineering Approval Committee; decides on GM research and release.
- 20Basmati patent 1997 by an American company; India has about 200,000 rice varieties and 27 documented Basmati varieties.
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Key terms
18 terms
- Explant
- Any plant part taken out and grown in a test tube on a sterile nutrient medium.
- Totipotency
- The ability of a single cell or explant to regenerate a whole plant.
- Micro-propagation
- Producing thousands of plants quickly by tissue culture.
- Somaclone
- A tissue-culture plant genetically identical to the parent it came from.
- Protoplast
- A plant cell whose wall has been digested away, bounded only by the plasma membrane.
- Somatic hybridisation
- Fusing protoplasts of two varieties and growing the hybrid cell into a plant.
- GMO
- An organism whose genes have been altered by manipulation.
- Bt toxin
- Insecticidal protein of Bacillus thuringiensis, stored as an inactive protoxin crystal.
- cry gene
- A gene coding for a Bt crystal toxin protein, such as cryIAc or cryIAb.
- RNA interference
- Silencing of a specific mRNA by a complementary double-stranded RNA that blocks its translation.
- C peptide
- The extra stretch in pro-insulin, removed when it matures into insulin.
- Gene therapy
- Correcting a gene defect by delivering a normal gene into a person's cells or an embryo.
- ADA deficiency
- Immune disorder caused by deletion of the gene for adenosine deaminase.
- Probe
- A radioactively tagged single-stranded DNA or RNA that finds its complementary sequence.
- ELISA
- Enzyme Linked Immuno-sorbent Assay: detects infection by antigen-antibody interaction.
- Transgenic animal
- An animal whose DNA has been manipulated to carry and express a foreign gene.
- GEAC
- Genetic Engineering Approval Committee, which rules on GM research and release in India.
- Biopiracy
- Using a country's bio-resources without authorisation and without compensatory payment.