Editing Genetic testing (section)

{{short description|Medical test}}
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{{About|genetic tests for disease and ancestry or biological relationships|use in genealogy and archaeology|genealogical DNA test|use in forensics|DNA profiling}}
{{Genetics sidebar}}
'''Genetic testing''', also known as '''DNA testing''', is used to identify changes in [[DNA]] sequence or [[chromosome]] structure. Genetic testing can also include measuring the results of genetic changes, such as [[RNA]] analysis as an output of [[gene expression]], or through [[biochemical analysis]] to measure specific [[protein]] output.<ref name="AMA">{{Cite web|url=https://www.ama-assn.org/delivering-care/precision-medicine/genetic-testing|title=Genetic testing|website=American Medical Association|language=en|access-date=2019-10-03}}</ref> In a medical setting, genetic testing can be used to diagnose or rule out suspected [[genetic disorders]], [[Predictive medicine|predict risks]] for specific conditions, or gain information that can be used to customize medical treatments based on an individual's genetic makeup.<ref name="AMA" /> Genetic testing can also be used to determine biological relatives, such as a child's [[biological parentage]] (genetic mother and father) through [[DNA paternity testing]],<ref>{{Cite web|url=https://americanpregnancy.org/prenatal-testing/paternity-testing/|title=Paternity Testing|date=2012-04-25|website=American Pregnancy Association|language=en-US|access-date=2019-10-03}}</ref> or be used to broadly predict an individual's [[ancestry]].<ref>{{Cite web|url=https://www.vox.com/science-and-health/2019/1/28/18194560/ancestry-dna-23-me-myheritage-science-explainer|title=The limits of ancestry DNA tests, explained| vauthors = Resnick B |date=2019-01-28|website=Vox|language=en|access-date=2019-10-03}}</ref> Genetic testing of plants and animals can be used for similar reasons as in humans (e.g. to assess relatedness/ancestry or predict/diagnose genetic disorders),<ref>{{Cite web|url=https://www.vgl.ucdavis.edu/|title=UC Davis Veterinary Genetics Laboratory {{!}} Animal DNA testing {{!}} forensic testing {{!}} animal genetic research and diagnostics|website=www.vgl.ucdavis.edu|access-date=2019-10-03}}</ref> to gain information used for [[selective breeding]],<ref>{{Cite web|url=https://www.bbc.co.uk/bitesize/guides/zqftrwx/revision/1|title=Selective breeding and gene technology|website=www.bbc.co.uk|access-date=2019-10-14}}</ref> or for efforts to boost [[genetic diversity]] in endangered populations.<ref>{{cite journal | vauthors = Hunter ME, Hoban SM, Bruford MW, Segelbacher G, Bernatchez L | title = Next-generation conservation genetics and biodiversity monitoring | journal = Evolutionary Applications | volume = 11 | issue = 7 | pages = 1029–1034 | date = August 2018 | pmid = 30026795 | pmc = 6050179 | doi = 10.1111/eva.12661 | bibcode = 2018EvApp..11.1029H }}</ref>

The variety of genetic tests has expanded throughout the years. Early forms of genetic testing which began in the 1950s involved counting the number of chromosomes per cell. Deviations from the expected number of chromosomes (46 in humans) could lead to a diagnosis of certain genetic conditions such as trisomy 21 ([[Down syndrome]]) or monosomy X ([[Turner syndrome]]).<ref name="Durmaz_2015">{{cite journal | vauthors = Durmaz AA, Karaca E, Demkow U, Toruner G, Schoumans J, Cogulu O | title = Evolution of genetic techniques: past, present, and beyond | journal = BioMed Research International | volume = 2015 | pages = 461524 | date = 2015 | pmid = 25874212 | pmc = 4385642 | doi = 10.1155/2015/461524 | doi-access = free }}</ref>  In the 1970s, a method to stain specific regions of chromosomes, called [[G banding|chromosome banding]], was developed that allowed more detailed [[Karyotype|analysis]] of chromosome structure and diagnosis of genetic disorders that involved large structural rearrangements.<ref>{{Cite web|url=https://www.nature.com/scitable/topicpage/karyotyping-for-chromosomal-abnormalities-298/|title=Karyotyping {{!}} Learn Science at Scitable|website=www.nature.com|language=en|access-date=2019-10-14}}</ref> In addition to analyzing whole chromosomes ([[cytogenetics]]), genetic testing has expanded to include the fields of [[molecular genetics]] and [[genomics]] which can identify changes at the level of individual genes, parts of genes, or even single [[nucleotide]] "letters" of DNA sequence.<ref name="Durmaz_2015" />  According to the [[National Institutes of Health]], there are tests available for more than 2,000 genetic conditions,<ref>{{Cite web|url=https://report.nih.gov/nihfactsheets/ViewFactSheet.aspx?csid=43|title=NIH Fact Sheets - Genetic Testing: How it is Used for Healthcare|website=report.nih.gov|access-date=2019-10-14|archive-date=2019-08-16|archive-url=https://web.archive.org/web/20190816230116/https://report.nih.gov/nihfactsheets/ViewFactSheet.aspx?csid=43|url-status=dead}}</ref> and one study estimated that as of 2018 there were more than 68,000 genetic tests on the market.<ref>{{Cite web|url=http://www.medscape.com/viewarticle/896361|title=10 New Genetic Tests Reach the Market Each Day|website=Medscape|access-date=2019-10-14}}</ref>