Editing Polymerase chain reaction (section)

===Selective DNA isolation===
PCR allows isolation of DNA fragments from genomic DNA by selective amplification of a specific region of DNA. This use of PCR augments many ways, such as generating [[hybridization probe]]s for [[Southern blot|Southern]] or [[Northern blot|northern]] hybridization and [[DNA cloning]], which require larger amounts of DNA, representing a specific DNA region. PCR supplies these techniques with high amounts of pure DNA, enabling analysis of DNA samples even from very small amounts of starting material.{{citation needed|date=August 2024}}

Other applications of PCR include [[DNA sequencing]] to determine unknown PCR-amplified sequences in which one of the amplification primers may be used in [[Sanger sequencing]], isolation of a DNA sequence to expedite recombinant DNA technologies involving the insertion of a DNA sequence into a [[plasmid]], [[phage]], or [[cosmid]] (depending on size) or the genetic material of another organism. Bacterial colonies ''(such as [[Escherichia coli|E. coli]])'' can be rapidly screened by PCR for correct DNA [[plasmid|vector]] constructs.<ref name="Hybrid">{{cite book |vauthors=Pavlov AR, Pavlova NV, Kozyavkin SA, Slesarev AI |year= 2006|chapter=Thermostable DNA Polymerases for a Wide Spectrum of Applications: Comparison of a Robust Hybrid TopoTaq to other enzymes|title=DNA Sequencing II: Optimizing Preparation and Cleanup|editor=Kieleczawa J|publisher= Jones & Bartlett|pages=241–57|isbn= 978-0-7637-3383-4}}</ref> PCR may also be used for [[genetic fingerprinting]]; a forensic technique used to identify a person or organism by comparing experimental DNAs through different PCR-based methods.{{citation needed|date=August 2024}}

[[File:Pcr fingerprint.png|thumb|upright|Electrophoresis of PCR-amplified DNA fragments: {{Ordered list|Father|Child|Mother}}<br />The child has inherited some, but not all, of the fingerprints of each of its parents, giving it a new, unique fingerprint.]]

Some PCR fingerprint methods have high discriminative power and can be used to identify genetic relationships between individuals, such as parent-child or between siblings, and are used in paternity testing (Fig. 4). This technique may also be used to determine evolutionary relationships among organisms when certain [[molecular clock]]s are used (i.e. the [[16S rRNA]] and recA genes of microorganisms).<ref>{{cite journal | vauthors = Pombert JF, Sistek V, Boissinot M, Frenette M | title = Evolutionary relationships among salivarius streptococci as inferred from multilocus phylogenies based on 16S rRNA-encoding, recA, secA, and secY gene sequences | journal = BMC Microbiology | volume = 9 | pages = 232 | date = October 2009 | pmid = 19878555 | pmc = 2777182 | doi = 10.1186/1471-2180-9-232 | doi-access = free }}</ref>