Download Biotech Applications: Genetically Modified Crops, RNA Interference, and Medicine and more Summaries Biology in PDF only on Docsity!
Biotechnology and its Applications
Genetically Engineered Crops
โ Genetically engineered crops have desirable genes (as of insect/pest resistance, giving better yield) incorporated in them. โ Genetically modified crops have โ more tolerance to abiotic stresses such as cold, drought, salinity, heat, etc. โ insect/pest resistance โ reduced post-harvest losses โ efficient mineral usage by plants โ enhanced nutritional value (e.g., Vitamin A rich rice)
Bt Cotton
โ Bacillus thuringiensis is a bacterium that produces proteins to kill certain insects such as lepidopterans (armyworm), coleopterans (beetles), and dipterans (flies/ mosquitoes). B. thuringiensis produces a protein crystal containing a toxic protein (inactivated state). โ Inactivated toxin Activated toxin (gut of insect) โ Activated toxin binds to the epithelial cells in the midgut of insect and creates pores that cause lyses and swelling and eventually death of insect. โ This toxin is encoded by a gene called Cry in the bacterium. Genes encoded by Cry IAc and Cry II Ab control cotton bollworms and those encoded by Cry IAb control corn borer. โ Cry genes are introduced into the cotton plants to produce Bt cotton, which is an insect resistant variety of cotton.
RNA Interference (RNAi )
โ RNAi is a method adopted to prevent infestation of roots of tobacco plants by a nematode Meloidegyne incognitia. โ In RNAi, a complementary RNA binds to mRNA to form a ds RNA,
which cannot translate and hence, its expression is blocked (Silencing). โ This complementary mRNA may come from โ infection by RNA viruses โ transposons (mobile genetic elements) โ RNAi exists naturally in eukaryotes as a method of cellular defence. โ Nematode specific genes (DNA) were introduced in the host plant. โ The introduced DNA forms both sense and anti-sense RNA. โ Two strands being complementary to each other bend and form ds RNA, leading to RNAi. โ mRNA of nematode is silenced and the parasite cannot survive in the transgenic host.
Applications of Biotechnology in Medicine
Recombinant Therapeutics
โ With the help of RDT, mass production of efficient therapeutic drugs can be accomplished. โ These are safe and do not induce unwanted immunological response.
Genetically Engineered Insulin
โ Insulin is in great demand due to increase in number of patients with adult onset diabetes. โ Insulin extracted from animal source (example, slaughtered cattle and pigs) induce allergy in humans. โ Insulin as a pro-enzyme consists of 3 peptide chains โ A, B, and C. โ Pro-enzyme insulin Mature insulin โ Mature insulin consists of only two peptide chains โ A and B. Both these chains were separately isolated and introduced in plasmids of E. coli to produce insulin chains. โ Separately produced chains A and B were extracted and combined by creating a disulphide bond to form mature human insulin.
Gene Therapy
appear in the photographic film since probe will not be able to bind with that part.
Transgenic Animals & Biopiracy
Transgenic Animals
โ Animals that have their DNA manipulated to possess or express an extra gene are called transgenic animals. โ Till date, transgenic rats, rabbits, pigs, sheep, cows, and fish have been produced.
Reasons for Producing Transgenic Animals
โ Study of normal physiology โ Transgenic animals serve as models to study genetics, regulation and down regulation of genes, and their corresponding effects on physiology. โ They give information about the biological role of a particular factor in the body. โ Study of diseases โ They act as models to study genetic basis of diseases. โ These studies aid in finding possible treatments of diseases. โ Transgenic models exist of various human diseases such as cancer, cystic fibrosis, rheumatoid arthritis, Alzheimerโs, etc. โ Biological products โ Treatment of diseases often requires certain products that are expensive to make. โ Transgenic animals can be produced that have genes, coding for that particular product. โ Example โ Human protein ฮฑ-1-antitrypsim used to treat emphysema is isolated by this method. โ In 1997, first transgenic cow Rosie produced human protein-enriched milk, which contained ฮฑ-lactalbumin and was nutritionally more suitable for human babies.
โ Vaccine safety tests โ Transgenic mice are used to test vaccines for their safety before they are used for humans. โ Example โ Transgenic mice are used to check polio vaccines. โ Chemical safety testing โ Transgenic animals contain genes that make them more sensitive to toxic substances than non-transgenic. โ Toxicity testing in such animals helps us to obtain results in less time.
Ethical Issues Associated with Transgenic Animals
โ Indian government has set up an organization GEAC (Genetic Engineering Approval Committee), which makes decisions regarding validity of GM research and its use for public utility. โ Modification which may result in the loss of biological significance of animals cannot go beyond regulation. โ Unpredictable results may be observed, if these organisms are introduced in natural ecosystem. โ Patents for transgenic varieties also create problems as many indigenous varieties are claimed by multinational companies as their own inventions. โ For example โ A new variety of Basmati was claimed by an American company through patenting. This new variety was actually derived by Indian farmers by crossing Indian Basmati with semi-dwarf varieties. โ Similarly Neem and turmeric, which have been used for ages in Indian medicines, are also matters of dispute for patent rights.
Biopiracy
โ Use of bio-resources by MNCs and other organisations without proper authorisation from countries and people concerned without compensatory payment โ Industrialized and developed nations are economically rich, but poor in biodiversity while opposite prevails for developing nations. Therefore, developed countries exploit traditional knowledge and resources of
