Understanding Different Types of DNA Tests
Your DNA is your genetic fingerprint, a unique identity that separates you from all other human beings. It can be found in your blood, saliva and other bodily fluid and tissues.
DNA can be used to identify both victims and perpetrators of crimes long after fingerprints have disappeared and weapons have been disposed of. DNA can be used to understand your past, plan for your future, determine who you are related to, and perhaps just as importantly, who you are not related to.
Your DNA is a molecule found in every cell in your body: A narrow string that is only one millionth of an inch long. The information in your DNA differentiates you from billions of other people and animals.
Different Kinds of DNA Tests
Most DNA tests can be classified for one of two purposes: "legal" or "peace of mind." Legal DNA tests may not be voluntary and may be court ordered. Results are admissible in court for issues relating to:
DNA tests are becoming more available for other uses, and can be used for helping people achieve "peace of mind." These are often used to determine paternity, but the results are not admissible in court. Testing can be done at home through kits that are mailed to labs. Other names for "peace of mind" DNA tests are:
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self sampling tests
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curiosity tests
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home tests.
DNA tests are used for many purposes other than determining paternity or in forensic investigations. Types of DNA tests include:
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Autosomal Testing (used to determine the "genetic percentages" of a person's ancestry from particular continents/regions)
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Mitochondrial DNA tests (which look at mtDNA in mitochondria to determine maternal ancestral lineage)
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Y-DNA Testing (which test segments of DNA on the Y chromosome - found only in males - to determine paternal lineage).
Ancestry DNA Testing
Genealogical DNA tests examine the nucleotides at specific locations on a person's DNA for the purpose of determining genetic genealogy.
Usually, tests compare the results of living individuals. Y-DNA test results can be used to confirm or disprove a suspected connection between two families. In most cases, ancestry DNA tests are used for peace of mind. In some instances, family ancestry DNA tests may be used to determine heirs, and may even be court ordered.
Mitochondrial DNA (mtDNA) Analysis
Mitochondrial DNA (mtDNA) is passed down from a mother to her offspring. In humans, between 10 and 100,000 copies of DNA exist in every cell (with the exception of egg and sperm cells). Unlike nuclear DNA, there is usually little or no change in mitochondrial DNA from mother to offspring.
Police and military officials have been able to use mitochondrial DNA analysis from hair, bones and teeth when other DNA tests cannot be performed. Mitochondrial analysis was used to identify victims of the September 11th attacks at the World Trade Center. These tests were legally admissible and provided peace of mind to the family members of the deceased.
Controversy Surrounding DNA Testing
DNA testing is controversial because it is often seen as an invasion of privacy. The FBI has a DNA data bank containing thousands of DNA profiles. The State of Virginia not only takes DNA samples from convicted felons, but also takes DNA samples of arrested suspects.
In spite of these concerns, DNA testing has freed criminals wrongly imprisoned for crimes and reunited family members separated at birth. People can use DNA testing to gain valuable insights about their ancestry, as well as learn about genetic diseases to which they may be susceptible. Most people agree that DNA testing results in more benefit to society than harm.
Resources
Block, D. (2005). DNA testing: The controversy of using it. Retrieved September 10, 2008, from the VOA news Web site: www.voanews.com/english/archive/2005-01/2005-01-13-voa6.cfm
Eurofins Genetic Services. (n.d.) DNA testing services. Retrieved September 10, 2008, from the Eurofins Genetic Services Web site: www.eurofinsgeneticservices.co.uk/dna-testing/
Riley, D.,Ph.D. (2005). DNA testing: An introduction for non-scientists: An illustrated explanation. Retrieved September 10, 2008, from the Scientific Testimony Web site: www.scientific.org/tutorials/articles/riley/riley.html
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