Introduction

 A bit about cloning and vectors

 What is cloning?

Cloning is the creation of an organism that is an exact genetic copy of another.

What is a vector? 

 
A vector is a DNA molecule used as a vehicle to transfer foreign genetic material into another cell.

It is basically of two types:
  1.   Cloning vector
  2. Expression vector
  • A cloning vector is a DNA molecule that has an origin of replication and is capable of replicating in a bacterial cell.
  • Expression vector is a plasmid containing the required regulatory sequences specifically used for the expression of a particular gene into proteins within the target cell.[2]

Most vectors are genetically engineered plasmids or phages. But cosmid vectors, bacterial artificial chromosomes, and yeast artificial chromosomes are also used. 

The vector used must harbour a suitable marker gene whose activity in the target cell can facilitate the identification of cells carrying it

  1. Antibiotic resistance-conferring markers
  2. Unmodified (wild-type) host must be sensitive the the chosen antibiotic
  • Ampicillin
  • Tetracycline
  • Chloramphenicol

Few of the generally used cloning vectors include:

  1. Plasmids
  2. Bacterophages
  3. Cosmids
  4. Yeast artifical chromosomes (YAC's)
  5. Bacterial arifical chromosomes (BAC's)

Image courtesy: Table 6.2, Principles and Techniques of Biochemistry and Molecular Biology , Wilson Keith and Walker John, seventh edition, cambridge university press, 2010

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Reference:

  • Principles of gene manupulations,S.B. Primrose, R.M.Twyman and R.W.Old, sixth edition, blackwell science.2004
  • http://www.biology-online.org/dictionary/Expression_vector
  • Principles and Techniques of Biochemistry and Molecular Biology , Wilson Keith and Walker John, seventh edition, cambridge university press, 2010