Editing Plasmid (section)

===Cloning===
{{main|Cloning vector}}
Plasmids are the most-commonly used bacterial cloning vectors.<ref name="uldis">{{cite book | vauthors = Geoghegan T | chapter = Molecular Applications | chapter-url=https://books.google.com/books?id=1wyf7pbR5z4C&pg=PA248 |title=Modern Microbial Genetics | veditors = Streips UN, Yasbin RE |publisher=Wiley-Blackwell |edition= 2nd |year= 2002 |isbn= 978-0471386650 |page=248 }}</ref> These cloning vectors contain a site that allows DNA fragments to be inserted, for example a [[multiple cloning site]] or polylinker which has several commonly used [[restriction sites]] to which DNA fragments may be [[Ligation (molecular biology)|ligated]]. After the gene of interest is inserted, the plasmids are introduced into bacteria by a process called [[transformation (genetics)|transformation]]. These plasmids contain a [[selectable marker]], usually an antibiotic resistance gene, which confers on the bacteria an ability to survive and proliferate in a selective growth medium containing the particular antibiotics.  The cells after transformation are exposed to the selective media, and only cells containing the plasmid may survive.  In this way, the antibiotics act as a filter to select only the bacteria containing the plasmid DNA.  The vector may also contain other [[marker gene]]s or [[reporter gene]]s to facilitate selection of plasmids with cloned inserts.  Bacteria containing the plasmid can then be grown in large amounts, harvested, and the plasmid of interest may then be isolated using various methods of [[plasmid preparation]].

A plasmid cloning vector is typically used to clone DNA fragments of up to 15 [[base pair|kbp]].<ref>{{cite book | vauthors = Preston A |chapter=Chapter 2 – Choosing a Cloning Vector |pages=19–26 |chapter-url=https://books.google.com/books?id=r6QC0hTwsrwC&pg=PA19  | veditors = Casali N, Preston A  |title=E. Coli Plasmid Vectors: Methods and Applications|series=Methods in Molecular Biology | volume = 235 |publisher=Humana Press |year= 2003  |isbn=978-1-58829-151-6}}</ref> To clone longer lengths of DNA, [[lambda phage]] with lysogeny genes deleted, [[cosmid]]s, [[bacterial artificial chromosome]]s, or [[yeast artificial chromosome]]s are used.