Cloning of Recombinant DNA

The bacteriophages or plasmids that have foreign DNA built into them in this manner are called vectors. Usually bacteriophages insert 

DNA very efficiently into their host bacteria. A single bacteriophage DNA can be replicated approximately 100-fold or more per cell depending on the type of phage and its host. 

Plasmids are small, circular DNAs that range in size from 2 to approximately 100 kb. They also can be amplified to approximately 20 copies per cell. In addition, plasmids can be introduced into bacterial cells, although less efficiently than phage vectors. Some plasmids can be used to introduce recombinant DNA into yeast cells. 

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Figure 15.3 Construction and cloning of recombinant DNA, with foreign DNA inserted into plasmid vector. Vector is introduced into cells, and bacteria containing recombinant DNA are selected by antibiotic resistance. The figure is not to scale.

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