DNA Testing
What is DNA testing? How is it performed? When is it required and how accurate is it? These questions have been asked countless times with the advent of this test. Simply, the test makes use of DNA fingerprinting of a sample and a reference - these can be taken from any part of the human body but are simplest in inner cheek cells.
A buccal swab is used to collect the sample from the inner cheek. The whole swab ends are then placed inside an Eppendorf tube and a lysis solution added to the tube - this procedure is done to burst the cells open for DNA to be released. The tube is then placed in a warm water bath. After this point of the DNA testing, the DNA is separated from the protein and debris from the bursting process. A concentrated salt solution is then added into the tube and the tube is covered. The tube is centrifuged and the liquid part used for DNA testing.
Genetic testing is then performed and the results of the fingerprinting are compared and matched. The test is very accurate - even reaching 100% in many cases. In fact, DNA testing is so accurate that confirmatory tests are not necessary but are still performed anyway.
Uses
DNA testing is required in cases where paternity is questionable or if a criminal case such as murder has evidence that could not be determined without matching the DNA to that of the suspect. Moreover, the test can be used for testing of infectious diseases or further research and development.
The paternity test makes use of samples from both the alleged father and the alleged child. This test works in the principle that a child inherits its DNA from both parents so that one strand would closely match that of one parent. To eliminate the mother's DNA result, the mother can be tested; however, "motherless" tests are just as accurate and could still determine the paternity of the child.
It is essential that the DNA testing is performed by an AABB-accredited DNA laboratory for the results to have legal bearing at all - for example, a prenatal paternity test can be ordered by the court.
