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Difference between Cloning Vector and Expression Vector

Cloning vectors are the DNA molecules that can carry a foreign DNA segment into the the host cell.The vectors used in recombinant DNA technology can be plasmids, cosmids, bacteriophages etc.
  • Plasmids: Self replicating, circular,  extra chromosomal DNA present in bacteria. Plasmids have only one or two copies per cell.
  • Bacteriophages: Virus infecting bacteria. Bacteriophages have high number per cell, so their copy number  is also high in genome.
  • Cosmids: Hybrid vectors derived from plasmids which contain cos site of lambda phage.
Feature required to facilitate cloning into vector: Origin of replication, Selectable marker, unique restriction sites.
The purpose of cloning vector is often to make numerous copies of the inserted gene.
Expression Vectors: The cloning vector containing suitable expression signals to have maximum gene expression, is called expression vector.
The following expression signals are introduced into gene cloned vectors to get maximum expression:
  • Insertion of a strong promoter.
  • Insertion of a strong termination codon.
  • Adjustment of distance between promoter and cloned gene.
  • Insertion of transcription termination sequence.
  • Insertion of a strong translation initiation sequence. pCI mammalian expression vector 
Example: An expression vector pSOMI containing promoter operator (PO) for production of a chain of somatostatin (somI).
Expression vector are designed for the expression of protein product coded by that inserted gene.


  1. this information is much more easy to understand remembering

  2. this information is much more easy to understand remembering

  3. Really good . but notify more example of expression vectors

  4. amazing site. happy

  5. So if there is a gene of interest for which one wants to produce a recombinant protein, how are the two types of vectors related or used? Does one first identify the gene, insert it into a cloning vector, amplify it and then transfer it into a prokaryotic cell for expressing the protein? Explanation of the steps generally followed to achieve this would be appreciated.

  6. Montasir Al-mansi25 February 2018 at 01:17

    very good information, but why not allow to copy this information ?


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