Multiple cloning site

A multiple cloning site (MCS), also called a polylinker, is a short segment of DNA which contains many (up to ~20) restriction sites—a standard feature of engineered plasmids.

The purpose of an MCS in a plasmid is to allow a piece of DNA to be inserted into that region.

The digested vector is cut with a restriction enzyme that complements the oligonucleotide insert overhangs.

This method can also be used to add new restriction sites to a multiple cloning site.Multiple cloning sites are a feature that allows for the insertion of foreign DNA without disrupting the rest of the plasmid which makes it extremely useful in biotechnology, bioengineering, and molecular genetics.

This design enables efficient identification of recombinant plasmids, as the insertion of foreign DNA into the MCS disrupts the marker gene, allowing for blue-white screening or other selection methods.

In order to genetically engineer insulin, the first step is to cut the MCS in the plasmid being used.

[8] Once the MCS is cut, the gene for human insulin can be added making the plasmid genetically modified.