Editing DNA–DNA hybridization (section)

== Method ==
The DNA of one organism is labelled, then mixed with the unlabelled DNA to be compared against. The mixture is incubated to allow DNA strands to dissociate and then cooled to form renewed hybrid double-stranded DNA. Hybridized sequences with a high degree of similarity will bind more firmly, and require more energy to separate them. An example is they separate when heated at a higher temperature than dissimilar sequences, a process known as "[[DNA melting]]".<ref>{{Cite book |last=Sinden |first=Richard R. |url=https://www.worldcat.org/oclc/30109829 |title=DNA structure and function |date=1994 |publisher=Academic Press |isbn=0-12-645750-6 |location=San Diego |pages=37–45 |oclc=30109829}}</ref><ref>{{Cite book |url=https://www.worldcat.org/oclc/818450218 |title=Tools and techniques in biomolecular science |date=2013 |publisher=Oxford University Press |others=Aysha Divan, Janice Royds |isbn=978-0-19-969556-0 |location=Oxford |oclc=818450218}}</ref><ref>{{Cite journal |last1=Forster |first1=A. C. |last2=McInnes |first2=J. L. |last3=Skingle |first3=D. C. |last4=Symons |first4=R. H. |date=1985-02-11 |title=Non-radioactive hybridization probes prepared by the chemical labelling of DNA and RNA with a novel reagent, photobiotin |journal=Nucleic Acids Research |volume=13 |issue=3 |pages=745–761 |doi=10.1093/nar/13.3.745 |issn=0305-1048 |pmc=341032 |pmid=2582358}}</ref>

To assess the melting profile of the hybridized DNA, the double-stranded DNA is bound to a column or filter and the mixture is heated in small steps. At each step, the column or filter is washed; then sequences that melt become single-stranded and wash off. The temperatures at which labelled DNA comes off reflects the amount of similarity between sequences (and the self-hybridization sample serves as a control). These results are combined to determine the degree of genetic similarity between organisms.<ref>{{Cite journal |last1=Hood |first1=D. W. |last2=Dow |first2=C. S. |last3=Green |first3=P. N. |year=1987 |title=DNA:DNA hybridization studies on the pink-pigmented facultative methylotrophs |journal=Journal of General Microbiology |volume=133 |issue=3 |pages=709–720 |doi=10.1099/00221287-133-3-709 |doi-access=free |issn=0022-1287 |pmid=3655730}}</ref>

A method was introduced to hybridize a large number of DNA samples against numerous DNA probes on a single membrane. The samples would need to be separated into individual lanes within the membrane, which would then be rotated to allow simultaneous hybridization with multiple DNA probes.<ref>{{Cite journal|last1=Socransky|first1=S. S.|last2=Smith|first2=C.|last3=Martin|first3=L.|last4=Paster|first4=B. J.|last5=Dewhirst|first5=F. E.|last6=Levin|first6=A. E.|date=October 1994|title="Checkerboard" DNA-DNA hybridization|journal=BioTechniques|volume=17|issue=4|pages=788–792|issn=0736-6205|pmid=7833043}}</ref>