DNA Paternity Testing
The genetic fingerprint; the building blocks of life; the silent witness. All of these terms can been used to describe DNA. DNA is present in every cell of the human body. Upon conception, a child will get 23-chromsomes from his/her biological mother and 23-chromosomes from his/her biological father. Together, these chromosomes combine to form a unique 23-pair combination (46 chromosomes in all). This unique marker is referred to as DNA, and once analyzed will match back against the DNA of the biological parents.
A paternity test is used to prove that a suspected father is or is not the biological father of a child. When a paternity test comes back showing that the 23-chromosomes within the child's DNA that do not belong to the biological mother also do not match those of the subject being tested then he can be excluded with 99.99% probability as the biological father. In order to arrive at the probability of paternity samples are collected from the biological mother, child and the suspected father. For most samples these are gained by the use of a buccal swab which will collect cells from inside the cheek of all tested parties. The swabs are then sent to a lab where they will extract DNA and extracted by means of an enzyme into fragments. Fragments are then placed into a gel matrix where electrical current will move the fragments across the surface of the gel revealing markers on the gel surface. These markers are then exposed to a probe that has been labeled with known DNA markers.
These probes can recognize and bind to a unique segment of the subject's DNA. The locations in which the probes bind to the DNA are the tell-tale descriptor of whether or not a paternal relationship exists. Much like developing a picture, a film will be developed from this gel matrix that reveals bands where the probes have bound to the subjects
If the band patterns of the suspected father do not match the band patterns of the child it can be conclusively determined that the person is in fact not the father of the child. On the other hand, if the patterns do match then the probability that the person in the child's mother or father begin to grow.
Once a suspected paternity match is established then the pattern matching will be done several times to independently verify the original match. In addition, different probes will then be introduces to produce different bands to further match up against the suspected father or mother. The more probes that are used, the more definitive the results can be.
Paternity testing is a relatively quick process when it comes to eliminating a suspected father or mother. Once a negative band match has been established, and then verified with at least one more independent test, then that person can be successfully disqualified from potential parenthood. However, when the bands do match then the time to determine definite parenthood can take several hours since each test must be verified independently and the number of probes is expanded to make a more definite match.
Though the most common use of this test is in child custody or child support cases where living parents and children are both present, it can be used also to establish paternity for parents who may no longer be living. This is often the case when questions of inheritance or family history come up. As long as there is a usable DNA sample from the deceased it can be used to test for paternity. In some cases, the body may actually be exhumed from burial to obtain a needed DNA sample – this is possible because our DNA is still present within our bones long after we have passed away.
In all, paternity testing is an accepted, reliable method that is employed by courts the world over to prove parenthood. It's relative ease of administration compared with testing results that are over 99% accurate make it the most reliable method available for determining parenthood.