Biology – Principles of genetic technology | e-Consult
Principles of genetic technology (1 questions)
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A vector is a DNA molecule that is used to carry foreign DNA (the recombinant DNA) into a host cell. It acts as a carrier, allowing the foreign DNA to be replicated and expressed within the host. Without a vector, it would be very difficult to introduce and maintain the recombinant DNA in a viable form.
Examples of commonly used vectors:
1. Plasmids:
- Advantages: Plasmids are small, circular DNA molecules found naturally in bacteria. They are easy to isolate and manipulate. They can replicate independently of the bacterial chromosome, allowing for high copy numbers of the recombinant DNA.
- Disadvantages: Plasmids typically have limited capacity for carrying large DNA fragments (usually up to 15 kb).
2. Viruses:
- Advantages: Viruses can efficiently deliver DNA into host cells, including eukaryotic cells. They can carry larger DNA fragments than plasmids.
- Disadvantages: Viral vectors can sometimes trigger an immune response in the host cell. They also require careful modification to remove harmful viral genes, making them more complex to construct.
Other vectors include artificial chromosomes (BACs, YACs) which are used for very large DNA inserts.