Cloning Vector

A cloning vector may be a small piece of DNA into which a far off DNA is often inserted for cloning purposes. A vector may be a DNA molecule that won't carry a far off DNA into the host cell. It has the ability to self replicate and integrate into the host cell. These vectors have played a major role in analyzing the molecular structure of DNA. Vectors are often a plasmid from the bacterium, a cell from the upper organism or DNA from an epidemic. The target DNA is inserted into the precise sites of the vector and ligated by DNA ligase. The vector is then changed into the host cell for replacement.


Features of Cloning Vectors

The cloning vectors possess the following features:

  • A cloning vector should possess an origin of replication in order that it can self-replicate inside the host cell.

  • It should be restricted for the insertion of the target DNA.

  • It should have a marker which is selectable with an antibiotic resistance gene that helps in the screening of the recombinant organism.

  • It should be small in size in order that it can easily integrate into the host cell.

  • It should be capable of inserting an outsized segment of DNA.

  • It should possess multiple cloning sites.

  • It should be capable of working under the prokaryotic and eukaryotic systems.


Types of Cloning Vectors

There are subsequent different types of cloning vectors:

Plasmids

  • These were the primary vectors utilized in gene cloning.

  • These are found in bacteria, eukaryotes, and archaea.

  • These are natural, extrachromosomal, self-replicating DNA molecules.

  • They possess antibiotic-resistant genes along with high copy numbers. 

  • They encode proteins that are necessary for their own replication.

  • pBR322, pUC18, F-plasmid are some of the examples of plasmid vectors

Bacteriophage

  • These are better than plasmids for cloning large DNA inserts.

  • Phage λ and M13 phage are commonly used bacteriophages in gene cloning.

  • 53 kb DNA is often packaged within the bacteriophage.

  • The screening of phage plaques is much easier than the screening of recombinant bacterial colonies.

Phagemids

  • These are artificial vectors.

  • They are used in combination with M13 phage.

  • They have multiple cloning sites and an inducible lac gene promoter.

  • They are identified by blue-white screening.

Bacterial Artificial Chromosomes

  • These are similar to E.coli plasmids vectors.

  • It is obtained from naturally occurring F’ plasmid.

  • These are used to study genetic disorders.

  • They can accommodate large DNA sequences without any risk.

Other Cloning Vectors include:

  • Yeast Artificial Chromosomes

  • Cosmids

  • Retroviral Vectors

  • Human Artificial Chromosomes

For a proper genomic DNA cloning, the DNA to be cloned is extracted from the organism of interest. Virtually any tissue source is often used (even tissues from extinct animals) as long as because the DNA is not extensively degraded. The DNA is then purified using simple methods to remove contaminating proteins (extraction with phenol), RNA (ribonuclease), and smaller molecules (precipitation and/or chromatography). Polymerase chain reaction (PCR) methods are often used for amplification of specific DNA or RNA (by a process known as Reverse-Transcription or RT-PCR) sequences prior to molecular cloning using primers or short DNA sequences specific for the region of interest. DNA for cloning experiments can also be obtained from RNA using polymerase(complementary DNA or cDNA cloning), or within the sort of synthetic DNA (artificial gene synthesis). cDNA cloning is usually utilized to obtain clones representative of the mRNA population of the cells of interest, while synthetic DNA is employed to get any precise sequence defined by the designer.


Conclusion

Cloning vectors are small pieces to insert foreign DNA into another cell and make multiple copies for an equivalent. The foreign DNA is replaced and expressed using the host cell machinery. It amplifies one copy of DNA into multiple copies.

FAQ (Frequently Asked Questions)

Q1. What is Cloning Vector?

Ans - A cloning vector may be a small piece of DNA into which a far off DNA is often inserted for cloning purposes. A vector may be a DNA molecule that won't carry a far off DNA into the host cell. It has the ability to self replicate and integrate into the host cell. These vectors have played a major role in analyzing the molecular structure of DNA. Vectors are often a plasmid from the bacterium, a cell from the upper organism or DNA from an epidemic. The target DNA is inserted into the precise sites of the vector and ligated by DNA ligase. The vector is then changed into the host cell for replacement.


Q2. What are the types of Cloning Vector?

Ans - The types of Cloning vector are - 

  • Plasmids

  • Bacteriophage 

  • Phagemids 

  • Bacterial Artificial Chromosome

Q3. What are Plasmids?

Ans - Plasmids are the primary vectors utilized in gene cloning. These are found in bacteria, eukaryotes, and archaea. These are natural, extrachromosomal, self-replicating DNA molecules. They possess antibiotic-resistant genes along with high copy numbers. They encode proteins that are necessary for their own replication. pBR322, pUC18, F-plasmid are some of the examples of plasmid vectors.