Applications of Biotechnology

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Applications of Biotechnology

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Description of Module Subject Name

Paper Name Module Name/Title

Applications of Biotechnology

Dr. Vijaya Khader Dr. MC Varadaraj

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1. Objectives

2. Introduction to Biotechnology

3. Explain about genetic engineering as an important tool in biotechnology.

4. Explain about applications of biotechnology in varied fields with examples.

5. Explain about ethical issues associated with Biotechnology.

2. Concept Map

Figure 1 : Applications of Biotechnology in varied fields Biotechnology

Forensic Sciences Plant

Biotechnology

Food Biotechnology

Industrial Biotechnology Pharmaceutical

Biotechnology Environmental

biotechnology

Animal Biotechnology

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3. Description

3.1 Introduction to Biotechnology

Biotechnology is defined as a set of tools that uses living organisms (or parts of organisms) to make or modify a product, improve plants, trees or animals, or develop microorganisms

for specific uses. Traditionally improvement in plants and animals were done through breeding or hybridization methods which were time consuming, laborious and may combine desirable traits with undesirable ones. In 1970s with the development in the field of molecular biology scientist were able to manipulate genes- which are basic physical and functional unit of hereditary and is made up of DNA. This technology is called as genetic engineering and is an important tool that allowed transfer of genes to any plant, animal or microbe resulting in generation of genetically modified organisms. Thus genetic engineering has allowed desired manipulation in a plant, animal or microbe in a more rapid manner compared to traditional breeding methods. Biotechnology has made an impact on varied field (Figure 1) like agriculture, medicine, genetically modified organisms, poultry, etc to name a few. In the following section we will discuss genetic engineering as an important tool in biotechnology and discuss about its applications in different fields.

3.2 Genetic engineering as an important tool in biotechnology:

Genetic engineering is the process that alters the genetic compliment of an organism by either removing some of the existing genes or by inserting new genes by making use of Recombinant DNA technology methods. The basic steps of genetic engineering are very much similar for a plant, animal or a microbial system. Figure 2 explains basic steps in genetic engineering to produce a transgenic plant or a genetically modified plant. There are 5 steps involved in the process which are as follows.

1. Plasmid DNA is isolated from the bacteria. Plasmids are extrachromosomal DNA materials that replicate independently of chromosomal DNA. It contains multiple cloning sites which allow easy cloning of foreign DNA to be cloned and selection markers that allow selection of recombinant plasmid during cloning process as well as selection of transformed plant cells.

2. The recombinant plasmid carrying the foreign gene of interest is transferred into the plant cell using a micro projectile gun.

3. Transformed plant cells are transferred aseptically to a suitable culture medium so that the cells divide.

4. The dividing cell mass is then transferred to suitable culture medium supplemented with hormones that allows plant regeneration.

5. Once the plants are hardened they are adjusted to the natural environment. The plants thus produced are known as transgenic plants.

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Figure 2. Steps involved in Genetic Engineering (Plant) 3.3 Plant Biotechnology

Plant Biotechnology is a field of biotechnology that results in improvement of plant health, quality and productivity. Traditionally plant breeding methods were practiced to select for beneficial characters of the plants. However the process requires selection for several generations so that plants with set of desired characters can be obtained. In last few years plant breeders have been able to precisely incorporate desired characters in the plants by making use of genetic engineering methods. Some of the plant biotechnological applications are discussed below.

3.3.1 Increased crop productivity

Biotechnology has allowed to improved plant productivity by introduction of characters such as disease resistance and drought resistance. Through genetic engineering and gene transfer methods researchers are now able to transfer the disease resistance and drought resistance genes into important agricultural crops. For example, researchers from University of

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Jember, Indonesia had developed transgenic sugar cane that expressed glycine betaine gene from Rhizobium meliloti resulting in 20-30% higher sugar production than its conventional counterpart during drought.

3.3.2 Pest resistance

Crop losses because of insect pests are huge resulting in considerable financial loss to farmers and decrease in crop productivity. Farmers typically make use of tons of chemical fertilizers to combat the insect pests, however consumers are not willing to eat such foods because of potential health hazards. Researchers are now able to generate transgenic crops such as corn, cotton, potato that express the Bacillus thuringensis toxin gene (Bt gene). When an insect consumes such a transgenic crop plant they also consume the toxin. The toxin becomes active when it reaches the alkaline environment of the insect digestive tracts. The active form of the toxin then inserts itself into the gut cell membrane resulting in formation of pores and breakdown of gut wall allowing spores and gut bacteria to enter the body. The insects ultimately dies of septicemia as the gut spores and microbes proliferate in the body. Growing such GM plants can eliminate the use of chemical pesticides and reduce the production cost.

3.3.3 Improved nutritional value

Use of recombinant DNA technology has allowed us to improve the food nutritional values. This can be a very important source of nutrients for the poor population in developing countries who suffer from malnutrition and nutrient deficiency. Golden rice had been one of the important applications of genetic engineering in plant biotechnology. The expression of β- carotene gene imparts a golden yellow color to the grain. The β- carotene is converted to vitamin A after digestion thus supplying the necessary vitamin A requirements. Other genetic engineering implementation in agricultural biotechnology includes increasing protein content in soya beans, amino acid content in beans etc.

3.3.4 Fruits and vegetables with improved shelf life:

Improved shelf life of fruits is another important application of agricultural biotechnology in which the ripening process. This allows long distance transport of fruits without damaging it and also increases its shelf life and flavor. Fruit ripening process involves degradation of the pectin component of the cell wall because of the activity of enzyme polygalactouronase (PG). Transgenic tomatoes were produced based on antisense technology in which the cDNA complementary to the PG gene was expressed thus preventing expression of PG gene.

3.3.5 Micropropogation

Normal vegetative propogation of plant is slow and seasonal. Hemce micropropogation technique is used for large scale laboratory multiplication of plants (Figure 3). The technique

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makes use of a small tissue of plant like leaf, stem etc as an explant which are surface sterilized and cultured in a suitable plant tissue culture medium supplemented with plant hormones. The regenerated plantlets are hardened in green house and ultimately planted in soil as normal plants. Micropropogation allows rapids multiplication irrespective of seasonal variations. It allows producing large number of plantlets in a small laboratory space. It also allows multiplication of sexually sterile hybrids and production of disease free plants.

Figure 3- Micropropogation of whole plants using plant tissue culture technique 3.4 Animal Biotechnology

Animal biotechnology makes use of genetic engineering and other biotechnological tools for improving animal health and productivity of animal based food products like meat, milk, eggs. In spite of the many biotechnological inputs to improve the animal health , the animals based food product are not yet delivered in global markets because of the ethical and public acceptance issues associated with development of transgenic animal and consumption of genetically modified animal based food products. Traditionally animal breeding methods were used for overall improvement in health of livestock and animals. However ever with the advent of biotechnology several biotechnological tools have been used for improvement of livestock.

Some of the animal biotechnological applications are represented below.

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3.4.1 Animal Cloning

In cloning process a somatic cell containing nucleus is fused with an enucleated egg cell by application of an electric shock. The fused egg is then cultured in appropriate nutrient medium till it develops into an embryo. The embryo is then transferred and transplanted into a surrogate mother. The resulting progeny with have the exact genetic complement to that of the somatic cell donor and is called its clone (Figure 4). The sheep ‘Dolly’ was the first ever mammalian clone that had been made through this technique in 1997 (Figure 5A). Dolly was also able to mate and produce offspring in a normal way suggesting that such cloned animals are reproductively fertile (Figure 5B). The advantage of the animal cloning is that a particular genotype that have been proven to be well adapted in a particular environment can be maintained indefinitely without any genetic changes that happen during reproduction.

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Figure4 Procedure of animal cloning

Figure 5 A– Dolly the cloned Sheep, B-Dolly and her lamb, Bonnie

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Figure 6 – Generation of knock out mice 3.4.2 Genetic Engineering in animals

Current research in genetic engineering of animals has potential application in medicine, agricultural applications and human health. Genetically modified organism like knock out mice (Figure 6) can be used as model systems for studying human diseases and for identification of important genes contributing to the disease condition. Genetically modified pigs may possibly be used as organ donors for human transplantations. Genetically modified animals can also be used for production of human therapeutic hormones like insulin.

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3.4.3 Animal agriculture

Animals are typically breed for production of important animal based food product like meat eggs, milk, etc. and also for recreational purposes. Through the use of biotechnology the animal health and productivity is enhanced. For eg the recombinant Bovine Somatotrophin hormone is injected in lactating cows to improve milk production.

3.5 Pharmaceutical biotechnology

Pharmaceutical biotechnology makes use of biological systems like plant animals or microbial cells and tissues for manufacture of pharmaceutically important products. These include many enzymes, proteins, hormones etc. Traditionally these pharmaceuticals products were directly extracted or obtained from their source material. Some of the source materials were dangerous and undesirable for eg- human chorionic gonadotrophin hormone was extracted from urine of pregnant women. With the advent of biotechnology and genetic engineering the production of these pharmaceutically important products was done by cloning the required gene sequence in appropriate biological systems like plants animals or microbes and products were harvested from the transformed cells in culture. Thus biotechnology helped overcome the issue of undesirable source material. Not only this, but it also ensures higher productivity (to meet the high medicine demand) and safety (so that transmission of pathogens like HIV virus in infected blood products can be prevented). Some of the pharmaceutically important products produced through use of biotechnology are explained below .

3.5.1 Therapeutic Hormone: Insulin

Insulin is a peptide hormone which is produced by β cells of pancreas. It is made up of 2 short polypeptide chains A and B linked together by disulphide bonds. It is required to control and regulate the blood glucose levels by stimulating it uptake into the cells. Lack of sufficient insulin production by the body leads to a development of disease condition known as insulin dependent diabetes mellitus or type I diabetes. Long term side effects of untreated diabetes include cardiovascular disease, stroke, kidney dysfunction, foot ulcers and damage to eyes. The blood glucose levels in such patients can be controlled by parenteral administration of such insulin preparations. Traditionally insulin hormone was prepared by extraction from pancreatic tissue of slaughter house animals followed by its purification by chromatographic methods.

However such animal derived insulin had side effects such as immunogenicity in humans and shortage of insulin because of limited number of slaughter house animals. These limitations

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paved the way to the use of recombinant DNA technology based production of insulin. Eli Lilly and company were the first pharmaceutical companies to produce recombinant human insulin by cloning and expressing the human proinsulin gene in E.coli. Expressed proinsulin peptide was purified and cleaved to obtain the final active insulin (Figure 7).

Figure 7: Maturation of proinsulin into insulin. The C peptide in the proinsulin is removed during its maturation into insulin.

3.5.2 Therapeutic enzymes- Anticoagulants : Hirudin

Hirudin is an anticoagulant first identified and isolated from medicinal leeches such as Hirudo medicinalis. It functions by inhibiting thrombin and ensures prolonged bleeding from the host after

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bite by such parasites. Hirudin directly acted upon and inhibited thrombin, it did not require any cofactor, and had been a weak immunogen and hence was considered as a potential therapeutic anticoagulant. Since enough enzyme could not be purified from the medicinal leeches it was never tested for its anticoagulant potential until the hirudin gene sequence was cloned and expressed in E.coli and other microbial systems in 1980’s. The recombinant Hirudin molecule was proven to be effective and safe in clinical trials.

3.5.3 Monoclonal antibodies-

A bacterial cell possesses a number of epitopes on the cell surface and injection of such a bacterial cell into a host system would result in development of a variety of B cells each interacting with a different epitope. Thus the resulting antiserum will contain a mixture of antibodies specific to the various epitopes. Such a response is known as a polyclonal response and the antibodies produced are known as polyclonal antibodies. However for experimental therapeutic and diagnostic purposes monoclonal antibodies are required which are antibodies produced by a single clone of B cells capable of identifying a single epitope.

Commercial production of monoclonal antibodies is done by hybridoma technology (Figure 8) introduced by Kolher and Milstein in 1975. In this technique antibody producing B cell is immortalized by fusion by myeloma cell line. The resulting hybrids produced large amount of monoclonal antibodies to be used for various purposes. So of the common applications of monoclonal antibodies are as follows.

Diagnostics- Small amount of drugs, toxins, proteins and hormones can be detected from various body fluids such as serum, blood, urine etc . For eg- Detection of HIV viral antigens use a test kit based on ELISA.

Therapeutic- Monoclonal antibodies can often be modified by conjugating it with a toxin or a radioisotope. Such monoclonal antibodies specific against cancer antigens can be used to specifically attack and kill cancer cell through the action of the conjugated toxin or radioactivity.

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Figure 8 – Hybridoma Technology for production of Monoclonal antibodies

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3.5.4 Vaccines

Vaccines are biological preparations of microorganism which are given with the aim to provide active immunity against a particular disease. Different types of vaccines are currently in use in market, however they have one or the other draw backs. The killed vaccines are inactive preparation of microorganism made through treatment with chemicals such as formaldehyde. Even though these are safe but they provide limited immunity and repeated booster doses are required for long lasting immunity. Live attenuated vaccines are live preparation of microorganism which is made nonpathogenic or avirulent through repeated subculture on a foreign host such as cells in culture. Live attenuated vaccines provide long lasting immunity since the cells are dividing however they may sometimes revert to its infectious form and cause disease. Subunit vaccines make use of purified proteins of pathogen as an antigen however there is high risk of infection to the workers who are handling large amount of pathogenic strains for isolation and purification of desired protein. Peptide vaccines are synthetically produced and constitute the antigenic part of the proteins. The major disadvantage with the use of subunit and peptide vaccines is their less antigenicity as they do not stimulate the immune system as strongly as a whole organism vaccine does.

Recombinant vaccines represent one of the major breakthroughs in production of vaccines. It makes use of genetic engineering based approach to generate various vaccines types and helps overcome some of the draw backs associated with traditional vaccines. For example nonpathogenic strains to be used as a live attenuated vaccines can be generated through genetic engineering where by the disease causing gene can be completely knocked out so that drawback of the strain reverting back to pathogenic form can be overcome. Similarly the subunit vaccine can be produced by cloning and expression of the antigenic protein gene into E.coli or other bacterial strains. This minimizes the handling of large quantities of pathogenic organism protecting the workers and well as environmental from hazardous due to accidental leakage of pathogenic microbes.

DNA vaccines are another important breakthough in production of vaccines in which the antigenic protein genes are isolated, cloned into appropriate vectors and are directly injected into muscles or skin cells of the to be immunized organism. Expression of the plasmid borne antigenic protein takes place directly in cells of immunized organism providing long lasting immunity. One of the major drawbacks with use of DNA vaccines is the possibility of integration of the plasmid into nuclear genes leading to new mutations that may be lethal or have side effects. These vaccines are still in experimental stages and clinical trial are not yet been done in humans because of the ethical issues associated with the use of DNA vaccines.

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3.6 Environmental Biotechnology

Environmental biotechnology deals will use of biotechnological tools to resolve issues related to environment contamination and preservation. Intervention of human activities leads to generate of waste from different industries, agricultural runoff as well as domestic waste are a few causes of environment contamination. These contaminants include pesticides, herbicides, fungicides, heavy metals, solvents, petrochemicals etc. These environmental pollutants affect growth of plants, animals and microbes. Some of these contaminants like pesticides and heavy metals are also toxic to human and animal health leading to diseases and even death. Thus restoration of environmental health is important to protect the living systems from the ill effects of contaminant and to improve quality of life. Some of the important applications of environmental biotechnology are listed below.

3.6.1 Pesticide degradation:

Pesticides are chemicals or compound intended for preventing growth or repelling different forms of pests including weeds, insects, rodents, mites etc. However the main concern with the use of pesticides is their persistent nature in the environment (Figure 9) and their effect on non-target organisms including human, animals, plants and microbes. Several laboratories worldwide are working on isolation and characterization of microbes capable of degrading several groups of pesticides eg organophosphate pesticide and nitroaromatic compounds. Some microorganisms capable of degradation of this group of compounds include Arthobacters, Rhodococcus, Pseudomonas species etc. These microorganisms express an enzyme named organophosphorous hydrolase encoded by the opd gene. Through the use of recombinant DNA technology the opd gene has been cloned and expressed in many bacterial systems such as E.coli, P. pseudoalkaligenes etc.

The biodegradation capabilities of such genetically modified bacteria can be further improved by metabolic engineering and manipulation of regulatory networks. These GM bacteria can be exploited for bioremediation of contaminated environments as well as biodegradation of industrial waste.

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Figure 9: Fate of pesticides in the environment

3.6.2 Biotechnology based bioconversion of agricultural biomass / waste into nutritive food Agricultural processes as well as waste from fruit and vegetable processing industries generate large quantities of biomass which is generally dumped or wasted. These wastes still contain a lot of nutrients in the form of cellulose, nitrogen and phosphorous compounds etc. which still can be exploited for various purposes. Mushroom cultivation technology is a field of biotechnology which cultivates edible as well as medicinal mushrooms by fermentation process and making use of such organic biomass as a substrate. This method converts the agricultural biomass into nutritive biomass which can be utilized for consumption and dietary purposes.

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3.6.3 Biosensors for monitoring of environmental contamination.

Biosensors are biosensing elements like enzymes, antibodies or biological cells based analytical devices used to detect presence of environmental pollutants. These sensing elements or cells are immobilized on the surface of the Biosensor. The enzymatic system catalyzes a biochemical reaction converting the substrate to the product. The amount of product formed during the reaction is directly proportional to the electrical signal generated by a transducer. The output from the transducer is amplified processed and recorded. Many biosensors have been developed for monitoring different kinds of environmental pollutants. Genetically modified yeast cells were used as whole cells biosensors to detect presence of estrogen molecules in polluted water.

Figure 10 Biosensor scheme

3.7 Food Biotechnology

The field of food biotechnology majorly deals with the use of use of microorganisms or enzymes produced by them for processing of inedible raw material into edible food products eg;

bread, cheese, alcoholic beverages curd etc. Some of the modern biotechnological applications of food biotechnology are discussed below.

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3.7.1 Cheese making

Cheese has been used as food product since more then hundreds of years. Traditionally cheese making process made use of calf rennet as a milk coagulant, however with the increasing food demands in India there is the available quantities of calf rennet were not enough. Additionally because of religious belief in India calf rennet was not a preferred enzyme source. Hence to produce large quantities of enzyme chymosin, biotechnological tools were used to clone and express the gene for calf chymosin enzyme in to E.coli and other hosts.

3.7.2 Vegetable and fruit juice

Many vegetable and fruit juice processing requires enzymes like pectinases, and cellulases in order to increases over all productivity. Pectinases enzyme can be extracted from fungus Aspergillus niger. Cellulases can be extracted from many fungi and bacteria that exhibit cellulolytic acitivity. Alternatively through genetic engineering the genes for these enzymes can be cloned and overexpressed to obtain large quantities of enzymes to be used vegetable and fruit processing.

3.7.3 Alcoholic fermentation using improved cultures.

Yeast strain used during beer making is selected on the basis of the flavour and aroma, imparted by the stain during fermentation. Fermentation rate ethanol tolerance osmotolerance oxygen requirements are the other parameters considered during selection of the strain. S.

cerevisiae strain is commonly used for commercial beer production. Many desirable properties can be incorporated into the strain to produce a GMO. Recently new brewing yeast strains have been produced with ability to ferment wider range of carbohydrates and produces beer with modified flavours.

3.8 Industrial Biotechnology

Industrial Biotechnology is a field of biotechnology which deals with production of chemical, materials and fuels by using renewable raw material as a substrate and living systems or enzyme extracted from them as catalyst for the bioconversion. Industrial biotechnology is gaining increasing importance because it has less energy consumption and hence lower production cost.

Additionally it also produces less greenhouse gases and thus is environmentally friendly. Lastly it also enables synthesis of valuable industrial products by making use of biological system of enzymes rather than chemicals thus benefiting our economy and environment.

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3.8.1 Increased production of important metabolites through metabolic engineering:

Metabolic engineering is an important tool of industrial biotechnology during which genetic manipulations of the enzymatic or regulatory pathways is done such that these changes favors enhanced expression and production of the product of interest. For Example C. glutamicum strain was modified by genetic engineering to produce as high as 136mM valine amino acid in 48 hrs.

Toxol is another important plant metabolite produced by plant Taxus brevifolia. It is an inhibitor of cell division used in treatment of ovarian and breast cancers. Originally it was extracted from the bark of Taxus species however the yield was considerably low. Later on through genetic engineering the Taxol gene as well as its regulatory factor was cloned in to S. cerevisiae leading to as much as 8.7 mg /Liter of taxol production. Some of the important applications of industrial biotechnology are explained below.

3.8.2 Lactic acid production

Lactic acid or 2 hydroxypropionic acid is an important chemical reagent commonly used for a number of purposes like as food preservative and decontaminant in meat processing, in detergent industry as a soap scum remover, in cosmetic industry as chemical exfoliant, any many more purposes. Traditionally D and L lactic acid was produced by Lactobacillus species during fermentation reaction. However these bacteria have special growth requirements like amino acids and sugarcane juice or corn steep liquor. Hence other bacterial systems like E.coli were modified through genetic engineering and were used for commercial production of D and L Lactic acid. In E.coli TG114 strain was designed to ferment hexoses by knocking out the genes for competing pathways and deleting the methyl glyoxal synthetase gene (msgA) to produce optically pure D Lactate with high productivity (Figure 11).

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Figure 11 – Metabolic engineering for production of optically pure lactic acid.

Gly3P, glycerol-3-phosphate; msgA, the methylglyoxal synthase gene; ldhA, the D-lactate dehydrogenase A; lldD, the L-lactate dehydrogenase gene; dld, the D-lactate dehydrogenase gene.

Multiple steps are indicated by consecutive arrows.

3.8.3 Biofuels:

Decreasing fossil fuel resources like petroleum, increasing cost of harvesting, processing and distribution of fossils fuels and environmental pollution associated with these processes are the major challenges faced by the world. These concerns have promoted the research and development studies on use of renewable energy sources like bioethanol, biodiesel etc. In chemical biodiesel production process lipids or triacylglycerol are esterified through transesterification reaction with short chain alcohols like ethanol. Vegetable oil or animal fat are commonly used as substrate or lipids for transesterification reaction. Researchers have engineered an E.coli strain by deleting the

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fadA gene encoding acyl COA synthetase involved in fatty acid degradation. The recombinant E.coli was capable of producing 0.024 g of fats/ h/ g dry cell mass. Researchers are also screening and investigating new microbial strain with potential to produce lipids to be used as substrate for biodiesel production.

3.9 Forensic science and Biotechnology

Forensic science is a field which deals with detection and investigation of crime based on the evidences found at the crime scene. Some forensic scientist travel to the crime site to collect the evidence themselves while others are involved in carrying out laboratory testing. DNA fingerprinting technique is commonly used to distinguish between different individuals by making use of DNA as sample. Any two humans or individuals of the same species has majority of their DNA sequences in common, hence sequences that are variable must be analyzed. Some of the biotechnological techniques used for forensic analysis are discussed below.

3.9.1 Restriction Fragment length polymorphism

The term Restriction Fragment length Polymorphism (RFLP) (Figure 10) refers to the difference between two homologous DNA samples that produce fragments of differing sizes upon restriction digestion with a restriction endonuclease. This difference in size of fragments produced can be because of presence of additional recognition site or absence of a recognition site for a particular restriction enzyme in the location of the genome analyzed. The RFLP analysis involves processing of the samples to extract DNA, digestion of the DNA with a particular restriction enzyme eg Eco RI , separation of the resultant fragments by agarose gel electrophoresis, southern blotting to transfer the fragments onto a membrane, probing of the membrane with specific probes that have been proven in the past to be specific heritable and suitable for RFLP analysis. On probing a specific DNA banding pattern will be generated that is specific for each individual.

3.9.2 PCR based analysis

An alternative method to RFLP analysis is a PCR based method (Figure 11) that is used to amplify the variable number of tandem repeat (VNTR). These are part of DNA containing specific sequences duplicated in variable number of times in different individuals. Eg one VNTR D1S80, present in chromosome number 1, is repeated from 16 – 40 times in different individuals. An individual homozygous for chromosome 1 will have equal number of repeats on both chromosomes and hence yield PCR product of same size. While an individual who is heterozygous for chromosome 1 will yield PCR products of two different lengths.

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Thus both methods are useful for forensic analysis however, the PCR based analysis is less time consuming and requires less sample.

Figure 10: DNA analysis by RFLP

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Figure 11: DNA analysis by PCR 3.9.3 Future of DNA typing methods:

The major issue associated with the DNA typing methods is amount of time required for processing of large amount of samples. New instruments and methodology are currently being developed with the aim of decreasing the time required for processing large amount of samples.

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3.10 Ethics in Biotechnology

Biotechnology is a fast growing field of biology because of its much application affecting every aspect of our lives, including food, clothing, medicine, health care, environment etc. It makes use of genetic engineering and other biotechnological tools for manipulating living cells or organism to generate a genetically modified organism (GMO) to be used for various purposes. Development of genetically modified organism, animal cloning, gene cloning are a few biotechnological applications that face criticism because of the ethical issue associated with it.

Different groups in the society have different views about biotechnology depending on their cultural back ground and previous experience. For example if a family has a child who is suffering from some disease that can only be cured only by use of recombinant DNA technology then they will have a different perspective as compared to that of family who has never been in such a situation. Many biotechnological studies make use of animals for clinical trial or drug testing etc. Many individuals such as animal liberationists are against the use of animals in biotechnology without considering the benefits that come from such research as they consider that the wellbeing of the animals is most important.

For example production of the food can be enhanced which will be very beneficial especially for developing countries that would allow them to produce sufficient food for their population. Not only the quantity of the food but the quality of the food can also be enhanced, for eg production of Golden rice. By use of pest resistant transgenic plants (eg BT Cotton), the use of chemical pesticides can be minimized, thus providing economic benefit and preventing the spray drifting into the neighboring plants as well as environmental contamination.

However some people argue against the use of such transgenic plants as it may cause allergic reactions in people. There is not enough research being done on the effect of the inserted gene from one species to another. The new species may escape into the wild environment and may result in production of super weeds formed by cross fertilization between wildtype and transgenic plant.

For some individuals genetic engineering in animals would not put their moral principles at risk, because some individual think that we have been doing selection hybridization, breeding methods for years to improve genetic characteristics of animals so genetic engineering can be seen as a continuation of selective breeding. So if genetic engineering creates animals that help us develop new human medicine then we must create genetically modified organism and use it. It may also help reduce the number of experimental animals models.

For other genetic engineering of animals may put their moral principles at risk. Some fear that the release of genetically modified organism may upset the natural balance of ecosystem. In addition

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some people are more acceptable to the use of genetically modified animals for biomedical application rather than as a food.

Such underlying complexity in the views of people regarding genetic engineering makes the setting of ethical limits difficult. However the limits of genetic engineering needs to be established based on public as well as expert opinion for especially those genetically modified organism that are intended to be released in the environment.