Recombinant DNA Technology- Gene Cloning

Keywords

Clone- A collection of molecules or cells, all identical to an original molecule or cell.

Gene Cloning- Leads to the production of multiple identical copies of the desired gene.

Recombinant DNA- A fragment of DNA, containing the gene to be cloned.

Genetic Engineering- Involves manipulating genes for practical purposes.

Plasmids- Small circles of DNA found in bacteria and some other organisms. Plasmids can replicate independently of the host cell chromosome.

Gene Cloning

Gene cloning is a method for identifying and purifying a particular DNA fragment (clone) of interest from a complex mixture of DNA fragments, and then producing large numbers of the fragment of interest.

Recombinant  DNA Technology or Genetic Engineering is the deliberate, controlled manipulation of the genes in an organism with the intent of making that organism is better in some way.

Recombinant DNA Technology covers all various experimental techniques that manipulate the genes of the organism. It uses recombinant DNA, molecular cloning, and transformation.

Steps of Gene Cloning

1  A fragment of DNA, containing the gene to be cloned, is inserted into a circular DNA molecule called a vector, to produce a recombinant DNA molecule.

 

2  The vector transports the gene into a host cell, which is usually a bacterium, although other types of a living cell can be used.

 

3  Within the host cell, the vector multiplies, producing numerous identical copies, not only of itself but also of the gene that it carries.

 

4  When the host cell divides, copies of the recombinant DNA molecule is passed to the progeny and further vector replication takes place.

 

5 After a large number of cell divisions, a colony, or clone, of identical host cells is produced. Each cell in the clone contains one or more copies of the recombinant DNA molecule;  the gene carried by the recombinant molecule is now said to be cloned.

 

Objectives of Gene Cloning

·        Obtaining a pure sample of a gene.

·        Gain information about the nucleotide sequence of the gene/ genetic mapping.

·        Alter the gene’s DNA sequence or to combine different DNA molecules together.

·        Protein/ Enzyme/ RNA function can be investigated.

·        Mutations can be identified, e.g. gene defects related to specific diseases.

·        Organisms can be ‘engineered’ for specific purposes, e.g. insulin production, insect resistance, etc.

Applications of Gene Cloning

·       Medical applications

-                     Insulin, somatostatin, human growth hormone.

-                     Blood clotting factor VII.

-                     Production of monoclonal antibodies, synthetic vaccines, etc.

·        Industrial applications

-         Protein/ Enzyme production.

-         Strain improvement/ new strain development.

-         Chemical and Food industries.

·        Agricultural applications

-         Genetically modified crops with a higher yield.

-         Disease/ stress-resistant crops.

-         Increasing overall protein yield and growth rate of farm animals.