Editing DNA profiling (section)

==Considerations in evaluating DNA evidence==
When using [[RFLP]], the theoretical risk of a coincidental match is 1 in 100 billion (100,000,000,000) although the practical risk is actually 1 in 1,000 because [[monozygotic twins]] are 0.2% of the human population.<ref>{{Cite book| vauthors = Schiller J |title=Genome Mapping to Determine Disease Susceptibility|publisher=[[CreateSpace]]|year=2010|isbn=978-1453735435}}</ref> Moreover, the rate of laboratory error is almost certainly higher than that and actual laboratory procedures often do not reflect the theory under which the coincidence probabilities were computed. For example, coincidence probabilities may be calculated based on the probabilities that markers in two samples have bands in ''precisely'' the same location, but a laboratory worker may conclude that similar but not precisely-identical band patterns result from identical genetic samples with some imperfection in the agarose gel. However, in that case, the laboratory worker increases the coincidence risk by expanding the criteria for declaring a match. Studies conducted in the 2000s quoted relatively-high error rates, which may be cause for concern.<ref>{{cite web | vauthors = Walsh NP | url = https://www.theguardian.com/crime/article/0,2763,640157,00.html | title = False result fear over DNA tests | archive-url = https://web.archive.org/web/20211025192300/https://www.theguardian.com/uk/2002/jan/27/ukcrime.research | archive-date=25 October 2021 | work = [[The Observer]] | date = 27 January 2002}}</ref> In the early days of genetic fingerprinting, the necessary population data to compute a match probability accurately was sometimes unavailable. Between 1992 and 1996, arbitrary-low ceilings were controversially put on match probabilities used in RFLP analysis, rather than the higher theoretically computed ones.<ref>{{cite book |title=The evaluation of forensic DNA evidence |date=1996 |publisher=National Academy Press |location=Washington, D.C. |doi=10.17226/5141 |pmid=25121324 |isbn=978-0309053952 | url = http://www.nap.edu/openbook/0309053951/html/35.html | archive-url = https://web.archive.org/web/20080830040631/http://www.nap.edu/openbook/0309053951/html/35.html | archive-date=30 August 2008 |author1=National Research Council (US) Committee on DNA Forensic Science: An Update }}</ref>

===Evidence of genetic relationship===
It is possible to use DNA profiling as evidence of genetic relationship although such evidence varies in strength from weak to positive. Testing that shows no relationship is absolutely certain. Further, while almost all individuals have a single and distinct set of genes, ultra-rare individuals, known as "[[chimera (genetics)|chimeras]]", have at least two different sets of genes. There have been two cases of DNA profiling that falsely suggested that a mother was unrelated to her children.<ref>{{cite web |url=https://abcnews.go.com/Primetime/story?id=2315693 |title=Two Women Don't Match Their Kids' DNA |publisher=Abcnews.go.com |date=15 August 2006 |access-date=3 April 2010 |archive-date=28 October 2013 |archive-url=https://web.archive.org/web/20131028052231/https://abcnews.go.com/Primetime/story?id=2315693 |url-status=live }}</ref>