[Biology Class Notes] on Cloning Vector Pdf

The cloning vector can be the small piece of the DNA in which the far-off DNA is inserted for cloning. The vector might be the DNA molecule that doesn’t carry the far-off DNA in the host cell. It has the capability of self-replication and integration in the host cell. The vectors have played a crucial role in the analysis of the molecular structure of the DNA. Vectors often tend to be plasmid from a bacterium, cells from the upper organism, or the DNA from the epidemic. The target DNA gets inserted at precise sites of the vector and ligated by the DNA ligase. Next, the vector is changed into a host cell for replacement. 

The Features of the Cloning Vectors

The features of the cloning vectors are as follows.

• The cloning vector must possess the origin of replication so that it can self-replicate within the host cell.

• It should be confined for insertion of target DNA. 

• It must have a marker that is selectable with antibiotic resistance gene which helps in screening recombinant organisms.

• It must be small in size so that it can be easily integrated within the host cell.

• It must be capable of inserting the outsized segment of the DNA.

• It must possess multiple cloning sites.

• It must work under eukaryotic and prokaryotic systems.   

The Different Types of the Cloning Vectors

Some of the different types of cloning vectors are Plasmids, Bacteriophage, Phagemids, bacterial artificial chromosomes, and others. We will take a brief look at some of the types of cloning vectors.

Plasmids

• These were the main vectors that were used in gene cloning.

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

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

• These vectors possess antibiotic-resistant genes with high copy numbers.

• They encode the proteins that are essential for their self-replication.

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

Bacteriophage 

• These vectors are better than the plasmids for the cloning of large DNA insertions.

• Phage λ and the M13 phage are the most common types of bacteriophages in gene cloning.

• 53 kb DNA is often packed in the bacteriophage. 

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

Conclusion

The cloning vectors are the small pieces for inserting the foreign DNA into another cell and then making numerous copies for the equivalent. The foreign DNA gets expressed and replaced using host cell machinery. It amplifies a single copy of the DNA into several copies.