Biotechnology and Bioinformatics (1+1)

2.1.3. Vectors

Vectors are the carrier DNAs into which ‘foreign’ DNAs or gene s of interest are spliced to make a recombinant DNA.

• Vectors along with this ‘foreign’ DNAs (i.e. recombinant DNA) are then introduced into appropriate host cell and are maintained for study or expression.
• Organisms with chimeric property can be produced with the help of cloning vectors.
• There are two types of vectors, cloning vectors and expression vectors.

i) Cloning vectors are used for obtaining millions of copies of clone d DNA segment. The cloned genes in these vectors are not expected to express themselves at transcription or translational level. Cloning vectors are used for creating genomic library or preparing the probe s or genetic engineering experiments or other basic studies. Most cloning vectors were originally derived from naturally occurring extrachromosomal elements such as bacteriophage s and plasmid s.

ii) Expression vectors allow the expression of cloned gene, to give the product ( protein ). This can be achieved through the use of promoters and expression cassettes and regulatory gene s ( sequence s). Expression vectors are used for transformation to generate transgenic plant, animal or microbe where cloned gene expresses to give the product. Commercial production of product of cloned gene may also be achieved by high level expression using the expression vectors.