Sunday, September 27, 2009

Genetic Engineering and Biotechnology and Basic Genetic- Engineering techniques


It is the manipulation of genetic material of any organism. Genetic engineering usually utilized bacterial cells and their plasmids, which are small circular DNA molecule. They can replicate freely within bacterial cells. Genetic engineering can produces cells that contain a foreign gene. These cells are capable of producing new and different protein. As a result of growth of these cells so many identical copies of plasmid with a foreign gene are produced. Basic steps in recombination of DNA technology are:

(1) Preparation of recombinant DNA (r DNA) molecule.

(2) Insertion of r DNA into host cell.

(3) Multiplication and production of numerous copies of host with r DNA in it.

(4) Selection of bacteria with required gene.


Free living plants in the environment that have a foreign gene inserted into than are said to be transgenic organisms or genetically engineered organisms. Plants in particular are easy to genetic manipulation because they can grow by tissue culture, where entire plant can be grow from single cell. Some techniques have been developed to produce transgenic plants. r DNA can be introduced into embryo or must be in cell wall-removed cell called protoplast. The only plasmid for transgenic plants cell is Ti Plasmid, transferred by its host Agro bacterium to many but not all plants.

Main aims of developing transgenic plants are:

(i) To cultivate more nutritious plants, seeds of these plants contain all amino acids required by human. Protein enhanced beans, soybeans, corn and what are now developed.

(ii) Plants require less fertilizer and are able to make rise of nitrogen from atmosphere.

(iii) Plants grow under harsh and unfavourable condition.


Gene sequencing is a method of determining mucleotide sequence of a gene (DAA molecules) developed in late 1970s by Fredrick Singer. This gene sequence can provide great deal of information. It is often the fastest way to determine the amino acid sequences of its polypeptide, more over; it provides the location of restriction site within a gene which can be manipulated further later on.

The main phases of gene sequencing are firstly to cut genes into specific small pieces, then each fragment is individually sequenced.

Most sequences that are determined are being collected in computer data bank that are valuable for biotechnology.

Genomic Library: It consist of genetic information of a species in a preferred environment. This library provides easy access to a preferred gene for its further copying or manipulation. In order to establish a genomic library of particular species, its DNA is fragmented by means of restriction enzymes and then the fragments are inserted into plasmids and bacteriophages which are introduced into bacteria. Such bacteria are cultured at controlled conditions so that they can be used later on.

Role of BioteChNology in diagnosis of diseases:

Biotechnology is now playing very important role in the diagnosis of infections as well as genetic diseases. The use of PCR and DNA propes in providing an excellent tool for the diagnosis of such diseases even before the onset of sumptoms. Medical scientists can now diagnose more than 200 genetic diseases using such technologies. Though hybridization alalysis, now it is possibleto detect abnormal alletic forms of genes present in DNA samples.


One of the potential benefits of genetic engineering is to treat genetic diseases in individuals. Theoretically it could be possible to replace or supplement the defective allele with a functional, normal allele. This could be inserted into somatic cells of the child or adult or into the germ cells or embryonic cells.

First illness likely to be treated by this techniques is called sever combined immuno deficiency disease (5CID) which is characterized by a very poor immune system. In this case the cells of bone marrow can not produce an enzyme called adenosine deaminase (ADA).

Gene therapy of germ live cells is another matter which has raised complex issues of safety and ethics. In this type recombinant DNA would be inserted into human sex cells so not only the treated individual be affected but so would all the individuals descendents.


In most cases genetic counselling entails predicting the chances of recurrence of condition that has already affected one or more members of a family. Such counselling depends first on precise diagnosis of disorder; the counsellor must be able to explain why the disorder occurred and how it is inherited. Counselling is important for parents of a child with genetic disorder such as cystic fibrosis, hemophilia, Down’s syndrome.

Some uses and applications of biotechnology in agriculture and medicine: Biotechnology brings revolution in the field of agriculture, medicine and other fields of biological sciences. One of the most important advantage of biotechnology in that it allows mass production of proteins which were difficult to obtain in past. Another field of biotechnology is the production of hormone. Human growth hormone produced by biotechnology is used to treat dwarfs. Insulin also produced by biotechnology is being used to treat diabetics. Biotechnology also contributes to diagnose by making DNA probes available. DNA probe is a specific sequence of single stranded DNA often radio active which binds by complimentary base pairing to a gene of interest.

Cotton, corn, potato and Soyabean plants have been engineered to be resistant to either insect predation or herbicides which are also environmentally safe. In 1999 transgenic crops were grown on more than 70 million acres around the world.

Biotechnology made progress in enhancing food quality of crops like soyabeans which produced oleic acid unsaturated fatty acid.

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