Asymmetric PCR
Asymmetric PCR is a variation of PCR used to preferentially amplify one strand of the original DNA more than the other.{{cite journal|title=Asymmetric PCR for good quality ssDNA generation towards DNA aptamer production|url=http://rdo.psu.ac.th/sjstweb/journal/34-2/0125-3395-volume-125-131.pdf|date=December 2011|first1=Marimuthu|last1=Citartan|display-authors=etal|journal=Songklanakarin J. Sci. Technol.|volume=34|issue=2|pages=125–131|access-date=2017-11-18|archive-date=2020-01-11|archive-url=https://web.archive.org/web/20200111040201/http://rdo.psu.ac.th/sjstweb/journal/34-2/0125-3395-volume-125-131.pdf|url-status=dead}} The technique has applications in some types of sequencing and hybridization probing where having only one of the two complementary strands is required.{{cite journal|title=Use of Asymmetric PCR to Generate Long Primers and Single-stranded DNA for Incorporating Cross-linking Analogs into Specific Sites in a DNA Probe|journal=Genome Res. |volume=6|date=1996 |issue=9|pages=886–892|doi=10.1101/gr.6.9.886|pmid=8889557 |first1=C I |last1=Wooddell |first2=R R |last2=Burgess|doi-access=free}}
Methodology
Asymmetric PCR differs from regular PCR by the excessive amount of primers for a chosen strand. Due to the slow (arithmetic) amplification later in the reaction (after the limiting primer has been used up) extra cycles of PCR are required.{{cite journal|title=Essential strategies to optimize asymmetric PCR conditions as a reliable method to generate large amount of ssDNA aptamers|first1=Mohammad|last1=Heiat|display-authors=etal|date=14 January 2017|doi=10.1002/bab.1507|pmid=27222205|journal= Biotechnology and Applied Biochemistry|volume=64|issue=4|pages=541–548|s2cid=21792777}}
A modification on this process, known as Linear-After-The-Exponential-PCR (LATE-PCR), uses a limiting primer with a higher melting temperature than the excess primer to maintain reaction efficiency as the limiting primer concentration decreases mid-reaction.{{cite journal|title=Linear-After-The-Exponential (LATE)–PCR: An advanced method of asymmetric PCR and its uses in quantitative real-time analysis|first1=J. Aquiles |last1=Sanchez|display-authors=etal|date=4 December 2003|volume=101|issue=7|doi=10.1073/pnas.0305476101|pmid=14769930 |journal=Proceedings of the National Academy of Sciences|pages= 1933–1938
|pmc=357030|doi-access=free }}
Applications
Asymmetric PCR can be used to form single stranded DNA from double stranded DNA, which is then used for DNA sequencing in the mutagenesis method.{{citation needed|date=November 2017}} Single stranded DNA is also important for aptamer generation.
References
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