Editing Virology (section)

===Cloning===
{{main article|Cloning vector}}
When purified viruses or viral components are needed for diagnostic tests or vaccines, cloning can be used instead of growing the viruses.<ref name="pmid32404960">{{cite journal |vauthors=Koch L |title=A platform for RNA virus cloning |journal=Nature Reviews. Genetics |volume=21 |issue=7 |pages=388 |date=July 2020 |pmid=32404960 |pmc=7220607 |doi=10.1038/s41576-020-0246-8 |url=}}</ref> At the start of the [[COVID-19 pandemic]] the availability of the [[severe acute respiratory syndrome coronavirus 2]] RNA sequence enabled tests to be manufactured quickly.<ref name="pmid32365353">{{cite journal |vauthors=Thi Nhu Thao T, Labroussaa F, Ebert N, V'kovski P, Stalder H, Portmann J, Kelly J, Steiner S, Holwerda M, Kratzel A, Gultom M, Schmied K, Laloli L, Hüsser L, Wider M, Pfaender S, Hirt D, Cippà V, Crespo-Pomar S, Schröder S, Muth D, Niemeyer D, Corman VM, Müller MA, Drosten C, Dijkman R, Jores J, Thiel V |title=Rapid reconstruction of SARS-CoV-2 using a synthetic genomics platform |journal=Nature |volume=582 |issue=7813 |pages=561–565 |date=June 2020 |pmid=32365353 |doi=10.1038/s41586-020-2294-9 |bibcode=2020Natur.582..561T |s2cid=213516085 |url=|doi-access=free }}</ref> There are several proven methods for cloning viruses and their components. Small pieces of DNA called [[cloning vector]]s are often used and the most common ones are laboratory modified [[plasmids]] (small circular molecules of DNA produced by bacteria). The viral nucleic acid, or a part of it, is inserted in the plasmid, which is the copied many times over by bacteria. This [[recombinant DNA]] can then be used to produce viral components without the need for native viruses.<ref name="pmid31219641">{{cite journal |vauthors=Rosano GL, Morales ES, Ceccarelli EA |title=New tools for recombinant protein production in Escherichia coli: A 5-year update |journal=Protein Science   |volume=28 |issue=8 |pages=1412–1422 |date=August 2019 |pmid=31219641 |pmc=6635841 |doi=10.1002/pro.3668 |url=}}</ref>