Genomic library and cDNA library both are used in gene cloning to isolate different DNAs. The difference between both of these libraries is that genomic library comprises DNA fragments which express the entire genome of an organism while in cDNA library, mRNA is taken from particular cells of an organism, and then cDNA consists of this mRNA in a reaction that is catalyzed by an enzyme.
|Basis||Genomic Library||cDNA Library|
|Definition||A genomic library is a collection of the complete genomic DNA from one organism. DNA is stored in a population of similar vectors, each containing a distinct insert of DNA.||A cDNA library is a blend of cloned cDNA fragments inserted into a selection of host cells, which collectively makes some part of the transcriptome of the organism.|
|Expression||Entire genome||Only specific genes.|
|Vector||It utilizes plasmids, cosmid, lambda phage, YAC and BAC for the accommodation of large fragments.||It’s no introns so utilizes plasmids, phagemids, lambda phage to accommodate modest fragments.|
What is Genomic Library?
In gene cloning procedure, the gene of interest is copied from DNA separated from an organism. When DNA is separated from an organism, its genes have been extracted at one time. DNA of organism comprises thousands of different genes. Genetic engineer finds one specific gene that encodes the particular protein of interest.
There’s absolutely no one method by which a particular gene from DNA are available, so scientists make gene libraries to catalogue the organism’s DNA. Scientists, then pick the desired gene in the library. Gene library is a group of living bacteria colonies which have been transformed with unique pieces of DNA in the organism that’s the origin of the desired gene. DNA is extracted from an organism to build a library that’s an organized form of DNA. Genomic library and cDNA are two kinds of gene libraries. Numerous techniques of gene cloning have been used as gene strategies in recombinant technology.
The DNA fragments are separated by cutting with specific restriction enzymes from parent DNA. These fragments are ligated to vector molecules, and the accumulated molecules are moved into host cells, 1 molecule in every cell. The genomic library is composed of introns, junk DNA, and a number of other fragments. Within this library, DNA is broken into smaller fragments inside a cell. Following this, all the small parts are inserted into a vector to create a library. The genomic library comprises all DNA of the whole genes and cell consists all their introns. Genomic DNA is the translation of the entire genome. It doesn’t code the whole part on one codon due to the size of introns. There isn’t any splicing mechanism at a genomic library that causes difficulty in the expression of genes taken from this library.
What is the cDNA Library?
cDNA library is constructed by choosing one tissue or cell type. Subsequently mRNA is isolated from that tissue or cell. A DNA copy of mRNA molecule consists of specific enzyme reverse transcriptase enzyme. So cDNA library contains that specific DNA that’s present in mRNA. No introns and no DNA sequence are found in this library. Within this library, all clones are full-length. Furthermore, a cDNA clone is essential to transfect cells for protein production or for cell-based assays.
Key Differences between Genomic Library and cDNA Library
- The genomic library was written directly of the genomic DNA.
- cDNA Library was formed by using mRNA as a template.
- The genomic library occupies entire genome of this organism.
- cDNA library represents only genes of particular ailments.
- Two enzymes, restriction endonucleases, and ligases are important for genomic library construction.
- Reverse transcriptase enzyme plays a significant role in cDNA library construction.
- The genomic library occupies the DNA of both prokaryotic and eukaryotic organisms.
- cDNA library represents the DNA of just eukaryotic organisms.
- cDNA library is capable of genome expression in bacteria that are prokaryotic since they lack introns.
- A genomic library isn’t capable of saying in the prokaryotic organism because they have introns and the prokaryotic organism doesn’t have any machines to process introns.