Genetic testing

This article is about genetic tests for disease and ancestry or biological relationships. For use in genealogy and archaeology, see genealogical DNA test. For use in forensics, see DNA profiling.
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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.[1] In a medical setting, genetic testing can be used to diagnose or rule out suspected genetic disorders, predict risks for specific conditions, or gain information that can be used to customize medical treatments based on an individual's genetic makeup.[1] 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,[2] or be used to broadly predict an individual's ancestry.[3] 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),[4] to gain information used for selective breeding,[5] or for efforts to boost genetic diversity in endangered populations.[6]

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).[7] In the 1970s, a method to stain specific regions of chromosomes, called chromosome banding, was developed that allowed more detailed analysis of chromosome structure and diagnosis of genetic disorders that involved large structural rearrangements.[8] 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.[7] According to the National Institutes of Health, there are tests available for more than 2,000 genetic conditions,[9] and one study estimated that as of 2018 there were more than 68,000 genetic tests on the market.[10]

  1. ^ a b "Genetic testing". American Medical Association. Retrieved 2019-10-03.
  2. ^ "Paternity Testing". American Pregnancy Association. 2012-04-25. Retrieved 2019-10-03.
  3. ^ Resnick B (2019-01-28). "The limits of ancestry DNA tests, explained". Vox. Retrieved 2019-10-03.
  4. ^ "UC Davis Veterinary Genetics Laboratory | Animal DNA testing | forensic testing | animal genetic research and diagnostics". www.vgl.ucdavis.edu. Retrieved 2019-10-03.
  5. ^ "Selective breeding and gene technology". www.bbc.co.uk. Retrieved 2019-10-14.
  6. ^ Hunter ME, Hoban SM, Bruford MW, Segelbacher G, Bernatchez L (August 2018). "Next-generation conservation genetics and biodiversity monitoring". Evolutionary Applications. 11 (7): 1029–1034. Bibcode:2018EvApp..11.1029H. doi:10.1111/eva.12661. PMC 6050179. PMID 30026795.
  7. ^ a b Durmaz AA, Karaca E, Demkow U, Toruner G, Schoumans J, Cogulu O (2015). "Evolution of genetic techniques: past, present, and beyond". BioMed Research International. 2015: 461524. doi:10.1155/2015/461524. PMC 4385642. PMID 25874212.
  8. ^ "Karyotyping | Learn Science at Scitable". www.nature.com. Retrieved 2019-10-14.
  9. ^ "NIH Fact Sheets - Genetic Testing: How it is Used for Healthcare". report.nih.gov. Archived from the original on 2019-08-16. Retrieved 2019-10-14.
  10. ^ "10 New Genetic Tests Reach the Market Each Day". Medscape. Retrieved 2019-10-14.