heteroduplex analysis
File:Formation_of_hetroduplexes_and_homoduplexes.jpg
Heteroduplex analysis (HDA) is a method in biochemistry used to detect point mutations in DNA (Deoxyribonucleic acid) since 1992.{{Cite book|title=PCR Mutation Detection Protocols|last=J. Wallace|first=Andrew|publisher=Humana Press, Totowa, New Jersey|year=2002|isbn=0896036170|editor-last=D. M. Theophilus|editor-first=Bimal|location=Totowa, New Jersey|pages=[https://archive.org/details/pcrmutationdetec00theo_0/page/151 151 - 164]|chapter=SSCP/Heteroduplex Analysis|editor-last2=Rapley|editor-first2=Ralph|chapter-url=https://archive.org/details/pcrmutationdetec00theo_0/page/151}} Heteroduplexes are dsDNA molecules that have one or more mismatched pairs, on the other hand homoduplexes are dsDNA which are perfectly paired.{{Citation|last1=Glavač|first1=Damjan|title=Heteroduplex Analysis|date=1996|work=Technologies for Detection of DNA Damage and Mutations|pages=241–251|editor-last=Pfeifer|editor-first=Gerd P.|publisher=Springer US|language=en|doi=10.1007/978-1-4899-0301-3_18|isbn=978-1-4899-0301-3|last2=Dean|first2=Michael}} This method of analysis depend up on the fact that heteroduplexes shows reduced mobility relative to the homoduplex DNA.{{cite journal | doi=10.1016/j.aca.2017.09.036 | title=A luminescent probe of mismatched DNA hybridization: Location and number of mismatches | date=2017 | last1=El-Yazbi | first1=Amira F. | last2=Wong | first2=Alysha | last3=Loppnow | first3=Glen R. | journal=Analytica Chimica Acta | volume=994 | pages=92–99 | pmid=29126473 }} heteroduplexes are formed between different DNA alleles.{{Cite journal|last1=White|first1=Marga Belle|last2=Carvalho|first2=Magda|last3=Derse|first3=David|last4=O'Brien|first4=Stephen J.|last5=Dean|first5=Michael|date=1992-02-01|title=Detecting single base substitutions as heteroduplex polymorphisms|journal=Genomics|volume=12|issue=2|pages=301–306|doi=10.1016/0888-7543(92)90377-5|pmid=1740339|issn=0888-7543}} In a mixture of wild-type and mutant amplified DNA, heteroduplexes are formed in mutant alleles and homoduplexes are formed in wild-type alleles.{{Citation|last1=Menounos|first1=Panayiotis G.|title=Chapter 4 - Mutation Detection by Single Strand Conformation Polymorphism and Heteroduplex Analysis|date=2010-01-01|url=http://www.sciencedirect.com/science/article/pii/B9780123745378000043|work=Molecular Diagnostics |edition=Second|pages=45–58|editor-last=Patrinos|editor-first=George P.|publisher=Academic Press|doi=10.1016/b978-0-12-374537-8.00004-3|isbn=978-0-12-374537-8|access-date=2019-12-02|last2=Patrinos|first2=George P.|editor2-last=Ansorge|editor2-first=Wilhelm J.}} There are two types of heteroduplexes based on type and extent of mutation in the DNA. Small deletions or insertion create bulge-type heteroduplexes which is stable and is verified by electron microscope.{{Cite journal|last1=Wang|first1=Y. H.|last2=Barker|first2=P.|last3=Griffith|first3=J.|date=1992-03-05|title=Visualization of diagnostic heteroduplex DNAs from cystic fibrosis deletion heterozygotes provides an estimate of the kinking of DNA by bulged bases.|url=http://www.jbc.org/content/267/7/4911|journal=Journal of Biological Chemistry|language=en|volume=267|issue=7|pages=4911–4915|doi=10.1016/S0021-9258(18)42917-1|issn=0021-9258|pmid=1537869|doi-access=free}} Single base substitutions creates more unstable heteroduplexes called bubble-type heteroduplexes, because of low stability it is difficult to visualize in electron microscopy. HDA is widely used for rapid screening of mutation of the 3 bp p.F508del deletion in the CFTR gene.