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Historical Background Of Biotechnology


Even though biotechnology developed as a unique branch of science only in the recent centuries, the application from this knowledge was familiar to man prior to 600 B.C.

  • Sumerians were skilled in distilling different types of beer.
  • There are clear records of the existence of distilling centres in Babylon and Egypt in the 3rd century A.D.
  • Around 1150 A.D., the preparation of ethyl alcohol by distillation process became a common practice and this process is used even today to manufacture ethyl alcohol on a large scale.
  •  The use of alcohol in Indian Ayurveda system has been a very ancient practice. The method of preparing food and medicine gradually attained new dimensions with the advent of technology.
  • In France, the method of artificial cultivation of mushroom was introduced in 1650.
  • Louis Pasteur explained the process of lactic acid fermentation.
  • Edward Buchner found out the technique of alcohol fermentation without using yeast in 1897. During the World War I, Germans used Buchner’s discovery to produce glycerol by industrial fermentation.
  • In 1915, a new technique of manufacturing yeast on a large scale for bakery use was developed in Germany.
  • In 1920s, Chaim Weizmann used the bacterium Clostridium acetobutylicum to produce butanol and acetone from starch.
  • In 1940, Penicillium notatum, a fungus, was used to produce the antibiotic penicillin during the World War II.
  • In 1950, the poliovirus was first cultured in mammalian cells to produce vaccines.
  • In 1960, enzyme immobilisation techniques were developed which were used to produce penicillin and fructose syrup.
  • Subsequently, considerable amount of researches in various fields of biology have led to the advent of modern practices in biotechnology.
  • However, the traditional practices of dairy farming, preparation of bread, wine etc. followed prior to the 20th century are not considered as biotechnological practices.

Biotechnological Processes


Modern technology has contributed a great deal to the development of biotechnology. Following are the major aspects of biotechnology.

Genetic Engineering
The technique of effecting desirable changes in the genetic material (DNA) of an organism is known as genetic engineering. The process involved in manipulating genes in the laboratory is called recombinant DNA technology. By this technique, it is possible to separate the desirable or useful gene from a cell and introduce it into another cell where the gene can undergo further replication.

At each stage of genetic engineering, i.e. isolation, changing and transferring of genes, we need molecular tools such as enzymes and vectors (Figure 14.1).

  • Restriction endonucleases (RENs): These are enzymes occurring naturally in bacteria as a chemical weapon against the invading viruses. These enzymes cut both strands of DNA and they can recognise and hydrolyse phosphoester bonds on a double-stranded DNA molecule. Hence they are called molecular scissors or molecule knives. The recognised site is named as the restriction site. As they cleave DNA at internal sites they are called endonucleases.
    RENs act only within a specific nucleotide sequence which exhibits reverse repeats around a given point of the strand. For example,
    5´G A A T T C 3´
    3´C T T A A G 5´
    Such sequences are called palindrome sequences or palindromes. They are similar to the words LIRIL, MALAYALAM etc.
    The action of RENs generates two types of cut ends, namely staggered ends and blunt ends. In a staggered cutting, there is a single-strand extension (overhanging or sticky ends), but in a blunt cutting there is no such extension.
  • DNA ligases: These enzymes are called molecular stitchers because these enzymes join any two cut ends of DNA.

Stages of Genetic Engineering


  • Vectors: These are also called the molecular vehicles because they carry the desired gene from the choice of organism to the organism of interest (host). The vector may be a plasmid, virus DNA or yeast. The plasmid is a small, extra-chromosomal circular DNA found in bacteria. Some of the plasmids used widely in genetic engineering are pBR 322, pUC 19 etc.

Applications of Genetic Engineering

Applications of Genetic Engineering 
Genetic engineering is a boon to mankind. It is being successfully employed in human welfare. The following are some of the applications:

  • It is used in the production of human insulin in E. coli system.
  • It is used to overcome the allergy caused by administering insulin from various animal sources. It has also reduced the cost of production.
  • It is used in the production of vaccines.
  • It is used in the production of human growth hormone.
  •  It is used in the production of monoclonal antibodies. The monoclonal antibody technology is a commercial venture and a boon to medical science. Monoclonal antibodies are produced by the hybridoma technique. It involves the fusion of myeloma (cancer) cells with the antibody-producing WBCs. The resulting hybrid cell is called hybridoma. The hybridoma cells can multiply like myeloma cells and produce antibodies such as WBC. This can be cultured in laboratory to produce a single type of specific antibody. Such antibodies are called monoclonal antibodies.
  • It is used in the production of transgenic organisms. Animals and plants which carry foreign genes are technically called transgenics or more popularly genetically modified organisms (GMOs). Some well-known examples of transgenic plants and animals are as follows:
  1. Transgenic plants
  • Transgenic potatoes have been produced with richer starch than ordinary tubers.
  • Herbicide tolerant crop plants have now been developed by genetically manipulating plant genomes resistant to specific herbicides.
  •  Transgenic cotton with Bt toxin from the bacterium Bacillus thuringiensis has been produced. Bt toxin, an endotoxin, kills a wide group of insect pests.
  • Flavr Savr tomato with delayed ripening and better nutrient quality are produced by genetic engineering.
  • The successful manipulation of β-carotene synthesis (a precursor of pro-vitamin A) in the rice grains gives them a characteristic yellow or orange colour. Hence, this rice which is genetically enriched with β-carotene is called as ‘Golden rice’. Golden rice is being developed to address vitamin A deficiency.
  1. Transgenic animals
  • Transgenic cattle with extra genes for growth hormones and casein give very high yield of milk.
  • Transgenic sheep with bacterial genes for growth hormones and casein give very high yield of milk.
  • Transgenic sheep with bacterial genes for synthesis of amino acid cysteine have higher yield of wool. Cysteine is raw material for the same.
  • Scientists are attempting to produce disease resistance animals, such as influenza resistant pigs.
  • Transgenic fishes getting growth hormone genes grow faster than normal fishes.
  • Transgenic pigs with human β-globulin gene produce human haemoglobin in their blood. This can be used for transfusion in man.

DNA Fingerprint Technology

DNA Fingerprint Technology
This is another useful technique in biotechnology used for identifying individuals by determining the genetic relationships. It was developed by A. Jeffery and his associates in 1985.

DNA fingerprinting technique basically involves breaking down the DNA sample of an individual using specific enzymes into short fragments and then separating the fragments using gel electrophoresis. The fragments get separated based on their size and net electrical charge. Larger fragments move more slowly compared to smaller fragments. As a result, a series of bonds are obtained in the form of a finger print. This is called DNA fingerprint. This characteristic pattern is unique to each individual (Figure 14.2).

Applications of DNA Fingerprinting

  • To settle disputed parentage: For determining the parentage of the child, 50% of bands in child’s DNA print should match with those of father’s DNA print and rest of the bands should match with those of the mother’s DNA print. If some of the bands in the child’s DNA print do not correspond with either the alleged father or alleged mother, then it is certain that they are not its real parents.
  • To settle murder, rape or theft cases: DNA fingerprint helps the police and courts of law to settle crime cases with 100% certainty.
  • It is used in pedigree analysis of animals and man.
  • Also employed in genetic analysis of various strains of agricultural crops and animals.

Tissue Culture

Tissue Culture
Plant tissue culture is a branch of biotechnology in which cells, tissues or organs of the plant body are isolated and grown on an artificial nutrient medium under the laboratory conditions (Figure 14.3).


DNA Fingerprinting Technique


body are isolated and grown on an artificial nutrient medium under the laboratory conditions

  • The tissues and organs of various plants are cultured to produce millions of plantlets on the media containing the plant hormones. Thus, they established a phenomenon of totipotency. It is the ability or potentiality of any living cell to produce the entire plant of its own type on the nutrient medium. Cellular totipotency was first proposed by German botanist Haberlandt in 1902. He thought that since each cell of the organism is derived from the fertilised egg and contains the same hereditary information, it should be able to regenerate the whole plant. However, Haberlandt’s experiment to grow isolated green cells failed. Success to grow isolated cells was achieved by F.C. Steward. But since totipotency was first proposed by Haberlandt, he is referred to as the father of plant tissue culture.
  • Sophisticated laboratory is required for tissue culture. Such a laboratory will have a media preparation room with laboratory, incubation chamber and culture room.
  • In general, the technique of tissue culture involves the following steps.
  1. Cleaning and sterilisation of glass wares such as culture tubes, flasks, pipettes, etc.
  2. Preparation and sterilisation of the plant materials.
  3. Surface sterilisation of the plant materials.
  4. Inoculation of the explants.
  5. Storage of cultures.


Tissue Culture


Applications of Tissue Culture

  • It is possible to obtain disease-resistant plant and high-yielding variety of plants through this technology.
  • It is possible to reduce the flowering period of many plants. For example, one can have two seasons of flowering in rose which normally has a single season.
  • It is possible to produce new varieties of plants by fusing different types of plant cells through germplasm hybridisation, e.g. pomato.
  • It has become possible to transfer nitrogen-fixing gene from bacteria into many higher plants by combining recombinant DNA technology and tissue culture to make those plants to meet their nitrogen requirement.
  • It is possible to develop a large number of plants in a limited space and in a short period of time.
  • It has also become possible to protect the desirable, pure characteristics of a plant by culture of pollen and parthenocarpic processes.


A population of identical molecular (genes) or cells or organisms all of which are derived from the same parent, by an asexual process, is called a ‘clone’. The process of producing genetically similar molecules, cells or organisms from a common precursor ‘in vitro’ or ‘in vivo’ is known as cloning.

  • Cloning of organisms is now a rapidly developing aspect of biotechnology. Daughter plants produced by strawberry runner and whole plants produced by tissue culture are examples of clones.
  • In 1997, Wilmut was successful in developing the world’s first clone of an adult sheep (Dolly). Thereafter, the technique has been tried in several other animals.

Steps in Cloning Experiment

  • Donor cells from udder of a Finn Dorset ewe were collected.
  • Collected cells were transferred to culture medium containing growth factors enough to keep cells alive.
  • Unfertilised eggs were collected from Scottish blackface ewe. The nucleus from the egg cell was removed.
  • The enucleated egg cell and the donor cells are fused subjecting them to gentle pulses of electricity.
  • The fused cell is transferred to a culture which allows division and growth.
  • The egg was then implanted into the uterus of blackface ewe which will act as surrogate mother.
  • After gestation period, the pregnant black-faced ewe gave birth to a baby Finn Dorset lamb, which was named Dolly.


Steps in Cloning


Application Cloning can be employed in the production of monoclonal antibodies (hybridoma technology).

A specific antibody produced by identical cells derived from a single parent cell is called a monoclonal antibody. Monoclonal antibody technology is a commercial venture and a boon to medical science. Monoclonal antibodies are produced by the hybridoma technique. It involves the fusion of myeloma (cancer) cells with antibody producing WBCs. The resulting hybrid cell is called hybridoma. The hybridoma cells can multiply like myeloma cells and produce antibodies such as WBC. This can be cultured in laboratory to produce a single type of specific antibody. Such antibodies are called monoclonal antibodies.

Applications of Biotechnology

Biotechnology, in general, and genetic engineering, in particular, have found a wide range of application in various manufacturing and service industries. Following are some of the major applications:

  • Biotechnology has significant application in agriculture. Its action ranges from improvement of plant and animal breeds to pest control and pathogen control.
  • Biotechnology is used in the food processing industry, in the production of acceptable additives.
  • Several techniques of biotechnology are employed in the synthesis of biocatalysts and biopolymers.
  • Biotechnological processes are employed in the control of pollution and treatment of polluted water.
  • The most significant contribution of biotechnology is in the field of health care; several vaccines, drugs, hormones (like insulin) are being produced on a large scale using genetic engineering techniques.

Limitations of Biotechnology

It is beyond any doubt that biotechnology has come as a boon to mankind, by providing products of importance in the fields of industries, food technology, healthcare, environmental engineering and so on. However, some of the procedures and processes that are being adapted in biotechnology have been against nature and natural laws.

  • Creation of new varieties of plants by using the technology of genetic engineering and tissue culture has resulted in certain advantages. However, closely associated with these advantages are certain disadvantages such as seed sterility.
  • Genetically modified foods have slowly started threatening the human health. Moreover, such attempts have upset the delicate balance existing in nature.
  • Cloning in particular has raised serious social, moral and ethical questions. There have been protests in many countries against attempts for human cloning.

In the light of the above consideration, it is necessary that the tools of biotechnology should be used properly and only for beneficial purposes and not for destructive activities.

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