Editing Mitochondrial DNA (section)

== Use in forensics ==
{{for|use in human identification|Human mitochondrial DNA}}
Unlike nuclear DNA, which is inherited from both parents and in which genes are rearranged in the process of [[Genetic recombination|recombination]], there is usually no change in mtDNA from parent to offspring. Although mtDNA also recombines, it does so with copies of itself within the same mitochondrion. Because of this and because the [[mutation rate]] of animal mtDNA is higher than that of nuclear DNA,<ref name="Brown">{{Cite journal |vauthors=Brown WM, George M, Wilson AC |date=April 1979 |title=Rapid evolution of animal mitochondrial DNA |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=76 |issue=4 |pages=1967–1971 |bibcode=1979PNAS...76.1967B |doi=10.1073/pnas.76.4.1967 |jstor=69636 |pmc=383514 |pmid=109836 |doi-access=free}}</ref> mtDNA is a powerful tool for tracking ancestry through females ([[matrilineage]]) and has been used in this role to track the ancestry of many species back hundreds of generations.{{cn|date=November 2024}}

mtDNA testing can be used by forensic scientists in cases where nuclear DNA is severely degraded. Autosomal cells only have two copies of nuclear DNA but can have hundreds of copies of mtDNA due to the multiple mitochondria present in each cell. This means highly degraded evidence that would not be beneficial for STR analysis could be used in mtDNA analysis. mtDNA may be present in bones, teeth, or hair, which could be the only remains left in the case of severe degradation. In contrast to STR analysis, mtDNA sequencing uses [[Sanger sequencing]]. The known sequence and questioned sequence are both compared to the Revised Cambridge Reference Sequence to generate their respective haplotypes. If the known sample sequence and questioned sequence originated from the same matriline, one would expect to see identical sequences and identical differences from the rCRS.<ref>{{Cite book |title=Forensic DNA typing: biology, technology, and genetics of STR markers |vauthors=Butler JM |date=2005 |publisher=Elsevier Academic Press |isbn=0-12-147952-8 |edition=2nd |location=Amsterdam |pages=241–242, 246, 258–259}}</ref> Cases arise where there are no known samples to collect and the unknown sequence can be searched in a database such as EMPOP. The Scientific Working Group on DNA Analysis Methods recommends three conclusions for describing the differences between a known mtDNA sequence and a questioned mtDNA sequence: exclusion for two or more differences between the sequences, inconclusive if there is one nucleotide difference, or inability to exclude if there are no nucleotide differences between the two sequences.<ref>{{Cite journal |vauthors=Syndercombe Court D |date=September 2021 |title=Mitochondrial DNA in forensic use |journal=Emerging Topics in Life Sciences |volume=5 |issue=3 |pages=415–426 |doi=10.1042/ETLS20210204 |pmc=8457767 |pmid=34374411}}</ref>

The rapid mutation rate (in animals) makes mtDNA useful for assessing the genetic relationships of individuals or groups within a species and also for identifying and quantifying the phylogeny (evolutionary relationships; see [[phylogenetics]]) among different species. To do this, biologists determine and then compare the mtDNA sequences from different individuals or species. Data from the comparisons is used to construct a network of relationships among the sequences, which provides an estimate of the relationships among the individuals or species from which the mtDNAs were taken. mtDNA can be used to estimate the relationship between both closely related and distantly related species. Due to the high mutation rate of mtDNA in animals, the 3rd positions of the codons change relatively rapidly and thus provide information about the genetic distances among closely related individuals or species. On the other hand, the substitution rate of mt-proteins is very low, thus amino acid changes accumulate slowly (with corresponding slow changes at 1st and 2nd codon positions) and thus they provide information about the genetic distances of distantly related species. Statistical models that treat substitution rates among codon positions separately, can thus be used to simultaneously estimate phylogenies that contain both closely and distantly related species<ref name="nature" />

Mitochondrial DNA was admitted into evidence for the first time ever in a United States courtroom in 1996 during ''State of Tennessee v. Paul Ware''.<ref>{{Cite journal |vauthors=Davis CL |year=1998 |title=Mitochondrial DNA: State of Tennessee v. Paul Ware |url=http://www.promega.ca/~/media/files/resources/profiles%20in%20dna/103/mitochondrial%20dna%20state%20of%20tennessee%20v%20paul%20ware.pdf |url-status=live |journal=Profiles in DNA |volume=1 |issue=3 |pages=6–7 |archive-url=https://web.archive.org/web/20160821232001/http://www.promega.ca/~/media/files/resources/profiles%20in%20dna/103/mitochondrial%20dna%20state%20of%20tennessee%20v%20paul%20ware.pdf |archive-date=21 August 2016 |access-date=21 October 2013}}</ref>

In the 1998 United States court case of Commonwealth of Pennsylvania v. Patricia Lynne Rorrer,<ref>[http://www.pacourts.us/assets/opinions/Superior/out/J-S62016-13m%20-%201016492591837697.pdf] {{Webarchive|url=https://web.archive.org/web/20160821222144/http://www.pacourts.us/assets/opinions/Superior/out/J-S62016-13m%20-%201016492591837697.pdf|date=21 August 2016}} Court case name listed in the appeal.{{full citation needed|date=August 2016}} Retrieved 17 April 2015.</ref> mitochondrial DNA was admitted into evidence in the State of Pennsylvania for the first time.<ref>[http://www.pfeifferbrunolaw.com/james-l-pfeiffer.html] {{Webarchive|url=https://web.archive.org/web/20150517002003/http://www.pfeifferbrunolaw.com/james-l-pfeiffer.html|date=17 May 2015}}{{self-published inline|date=August 2016}} Defense lawyer. Retrieved 17 April 2015.</ref><ref>{{Cite news |date=11 March 1998 |title=DNA Tests Got Rorrer Life in Jail |work=[[The Morning Call]] |vauthors=Garlicki D}}</ref> The case was featured in episode 55 of season 5 of the true crime drama series [[Forensic Files (season 5)]].<ref>{{Citation |title=Forensic files. a woman scorned Episode 55 Episode 55 |vauthors=Pellegrino P, Thomas P |date=2000 |work=Courtroom Television Network |publisher=Medstar Television |language=en |oclc=456260156}}</ref>

Mitochondrial DNA was first admitted into evidence in [[California]], United States, in the successful prosecution of David Westerfield for the 2002 kidnapping and murder of 7-year-old [[Murder of Danielle van Dam|Danielle van Dam]] in [[San Diego]]: it was used for both human and dog identification.<ref>{{Cite web |date=18 February 2005 |title=Judge allows DNA in Samantha Runnion case |url=http://www.nctimes.com/articles/2005/02/18/news/californian/lake_elsinore/22_48_212_17_05.txt |access-date=4 April 2007 |agency=Associated Press}}</ref> This was the first trial in the U.S. to admit canine DNA.<ref>{{Cite web |date=5 December 2013 |title=Canine DNA Admitted In California Murder Case |url=http://legal.pblnn.com/pit-bulletin-legal-news-radio/97-disclaimer |archive-url=https://web.archive.org/web/20140202165809/http://legal.pblnn.com/pit-bulletin-legal-news-radio/97-disclaimer |archive-date=2 February 2014 |access-date=21 January 2014 |website=Pit Bulletin Legal News}}</ref>

The remains of [[Richard III of England|King Richard III]], who died in 1485, were identified by comparing his mtDNA with that of two matrilineal descendants of his sister who were alive in 2013, 527 years after he died.<ref>{{Cite news |author-link=Maev Kennedy |date=4 February 2013 |title=Richard III: DNA confirms twisted bones belong to king |url=https://www.theguardian.com/science/2013/feb/04/richard-iii-dna-bones-king |url-status=live |archive-url=https://web.archive.org/web/20190108031920/https://www.theguardian.com/science/2013/feb/04/richard-iii-dna-bones-king |archive-date=8 January 2019 |access-date=7 December 2014 |work=The Guardian |vauthors=Kennedy M}}</ref>