BIOTECHNOLOGY Genetic engineering also referred as recombinant DNA technology or gene splicing is one kind of biotechnology involving manipulation of DNA It deals with the isolation of useful genes from a variety of sources and the formation of new combinations of DNA (recombinant DNA) for repair, improvement, perfection and matching of a genotype. Thus genetic engineering may be defined as a technique for artificial and deliberately modifying DNA (gene) to suit human needs. In genetic engineering manipulation breakage of DNA molecule of two desired places with the help of rectriction endonuclease to isolate a specific DNA segment and then insert it in another DNA molecule at a desired position. The new DNA molecule is recombinant DNA and the technique called genetic engineering. Genetic engineering aims at adding, removing or repairing of a part of genetic material. Genetic engineering can be used to improve the quality of human life. The construction of the first recombinant DNA emerged from the possibility of linking a gene encoding antibiotic resistance with a native plasmid (autonomously replicating circular extra chromosomal DNA) of Salmonella typhimurium. Stanley Cohen and Herbert Boyer accomplished this in 1972 by isolating the antibiotic resistance gene by cutting out of piece of DNA from a plasmid which was responsible for conferrring antibiotic resistance. The cutting of DNA at specific locations became possible with the discovery of the so called molecular scissors - restriction enzymes. The cut piece of DNA was then linked with the plasmid DNA. These plasmid DNA act as vectors to transfer the piece of DNA attached to it. Paul berg (Father of genetic engineering). He transferred gene of SV 40 virus (simian virus) in to E.coli with the help of LAMBDA phage. (Nobel prize - 1980) The concept of genetic engineering was the outcome of two very significant discoveries made in bacterial research. These were presence of extrachromosomal DNA fragments called plasmids (Magic circle) in the bacterial cell, which replicate along with chromosomal DNA of the bacterium presence of enzymes restriction endonucleases which cut DNA at specific sites. These enzymes are, therefore, called molecular scissors.
Posted on: Sat, 08 Mar 2014 15:08:24 +0000
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