The insert capacity of a cosmid vector is about 35-45 kb.

A cosmid has the characteristics of a hybrid plasmid. They are used in the building of genomic libraries. They are ~200 base pairs long. More detailed information is available on Wikipedia.

The first step is restriction of the cosmid and the foreign DNA with the restriction enzyme, then ligating the fragments together. Thereafter, the cosmids are loaded into the phage capsid, which leads to the expression of the foreign gene through transduction.

cosmids can accept insert fragments of DNA from 30-50 kilobases but plasmids can only accept inserts that are up to 15kb only.

it is a ds DNA use in recombinant DNA technology to insert our interested gene and multiply it.Ex;plasmid,cosmid