What is the Difference Between Plasmid and Cosmid?
🆚 Go to Comparative Table 🆚Plasmid and cosmid are both types of cloning vectors used in genetic engineering. They are circular double-stranded DNA molecules that replicate independently of the host's chromosomal DNA. However, there are some differences between them:
- Origin: Plasmids are naturally occurring extrachromosomal DNA molecules found in bacteria and archaea, while cosmids are hybrid vectors constructed from cos sequences of lambda phage DNA and plasmid DNA.
- Size: Plasmids can bear up to 25 kb of DNA fragments, whereas cosmids can contain up to 45 kb of DNA fragments.
- Cos sites: Cosmids contain special sticky ends known as cos sites, which are required for in vitro packaging. Plasmids do not have these cos sites.
- Lambda phage mediated transduction: Cosmids can be transmitted via lambda phage-mediated transduction due to their cos sites, which is not possible with regular plasmids.
- Origin of replication: Both plasmids and cosmids have an origin of replication (Ori), which ensures their replication within the host cell independent of the host genome replication.
In summary, plasmids are naturally occurring extrachromosomal DNA molecules, while cosmids are hybrid vectors constructed from cos sequences of lambda phage DNA and plasmid DNA. Both are used as cloning vectors in recombinant DNA technology, but they have differences in size, cos sites, and transmission methods.
Comparative Table: Plasmid vs Cosmid
Here is a table comparing the differences between plasmids and cosmids:
| Feature | Plasmid | Cosmid |
|---|---|---|
| Definition | A plasmid is a small, circular, double-stranded extrachromosomal DNA present in bacteria and archaea. | A cosmid is a hybrid vector constructed from cos sequences of lambda phage DNA and plasmid DNA. |
| Carrying Capacity | Plasmids can bear up to 25 kb of DNA fragments. | Cosmids can contain up to 45 kb of DNA fragments. |
| Use | Plasmids are often used for cloning and gene expression studies. | Cosmids are useful for constructing genomic libraries and studying large DNA fragments. |
| Vector Type | Plasmids are naturally occurring DNA molecules found in bacteria and archaea. | Cosmids are genetically engineered plasmids that include a lambda phage cos site. |
Both plasmids and cosmids are used in genetic engineering, but they differ in their ability to carry DNA fragments, their natural occurrence, and their uses in research.
- Cosmid vs Phagemid
- Plasmid vs Transposon
- Plasmid vs Vector
- Genomic vs Plasmid DNA
- Plasmid vs Chromosome
- Plasmid vs Episome
- Plasmid DNA vs Chromosomal DNA
- F Plasmid vs R Plasmid
- Genomic DNA vs Plasmid DNA Isolation
- Transposon vs Retrotransposon
- DNA Transposons vs Retrotransposons
- Protoplast vs Protoplasm
- Cisgenesis vs Transgenesis
- Cytoplasm vs Protoplasm
- Hybridization vs Cloning
- DNA vs cDNA
- Composite Transposons vs IS Elements
- Gene Cloning vs PCR
- rDNA vs cDNA