Outline and scope of Genetic Engineering in modern science

Introduction

The manipulation of genetic make up of living cells by inserting desired genes through a DNA vector, is called genetic engineering. In France this technology is called bio molecular engineering. For the first time Stanley Cohen and Herbert Boyer in 1973 designed a methodology for transferring certain genes from one organism to another. Now it is a popular technique in all most all branches of Biology.

Gene

The gene is a small piece of DNA that encodes for a specific protein. The gene is inserted into a vector DNA so that a new combination of vector DNA is formed. The DNA formed by joining DNA segments of two different organisms is called recombinant DNA or r DNA or chimeric DNA. The gene is introduced into a cell in the form of recombinant DNA. The gene manipulation therefore is known as recombinant DNA technology. The organism whose genetic make up is manipulated using recombinant DNA technique is called genetically manipulated organism. Genetic engineering has many applications in agriculture, animal sciences, industry and medicine.

Methodology of genetic engineering

Genetic engineering is a novel technique to create new strains of organisms with desired characters in short duration. The procedure of gene cloning is much sophisticated and need sophisticated instruments. The various steps involved in genetic engineering are preparation of desired genes, Isolation of DNA vector, Construction of recombinant DNA, Introduction of recombinant DNA into the host cell, Selection and manipulation of recombinant host cells, finally expression of clone gene.

Preparation of desired gene

The desired genes can be prepared in three ways. In the first method it is isolated from the total genomic DNA of an organism. To isolate a gene, the genomic DNA is cut into many pieces by treating with a restricting enzyme. They are separated on the basis of their lengths using electrophoresis. In the second method desired gene is prepared from mRNA of the gene by reverse transcription. The resultant DNA is called complementary DNA. In the third method the desired gene is prepared by using a computerized machine called gene machine. The machine can synthesize DNA of thousand nucleotides length according to predetermined sequence.

Isolation of DNA vector

The DNA used to transfer desired DNA into a host cell or an organism is known as a vector. The vector is also known as cloning vector, carrier molecule, cloning vehicle or vehicle. There are two types of cloning vectors namely plasmids and DNA of viruses. The successful cloning vectors should have genetic makers for identification of recombinant and genes for self multiplication in the host cells. A suitable cloning vector is chosen and isolated for gene cloning.

Construction of recombinant DNA

The desired DNA is inserted into the vector DNA using a restriction enzymeand DNA ligase. The resulting vector DNA containing the desired DNA is called recombinant DNA or recombinant vector.
The recombinant DNA can be introduced into the host cell by direct transformation, pathological agent, liposome fusion, and direct introduction. Bacterial cells intake the recombinant DNA s in the medium by direct transformation. The pathological agents like bacteriophage and agrobacterium pickup the recombinant DNA and introduce into the host bacteria cells or plant cells.
After culturing the host cells are screened for the presence of recombinant DNA. The recombinant host cells are selected from non recombinant cells using various methods. The selected cell containing recombinant DNA is called recombinant or clone. They are mass cultured to test the purity of the products of the cloned genes.

Expression of Cloned Gene

The desired gene expresses in the form of protein. The protein is isolated and tested immunologically. The recombinant producing pure product can readily be used in future. Here the gene is made to express in a new environment.
It has many applications in agriculture, health and industry. Moreover it is significant in medical field. Required manipulation can be done easily in any bacteria to induce new variations which are useful for man. Even serious diseases can be cured in near future.