How a Paternity Test Works
Paternity testing is the basic term
used for determining the father of a child. Because
everyone is born with a specifically unique DNA
structure (the building blocks of life) whose
characteristics are related to their parents’ DNA
structure, determining parentage is a simple and
definitive process. The testing of DNA has become
the generally accepted method of determining
paternity.
Types of DNA testing
There are two main types of DNA
testing that are used in paternity testing. One is PCR which takes a section of the DNA from the
sample given from the donor and then these same
sections are produced by a lab and highlighted with
fluorescent tags to show sections that will be
compared.
A second type of DNA testing, with
RFLP, takes the DNA sample and uses enzymes to break
the DNA sections apart so that an electric current
can be used to segregate the DNA by size. They are
then identified by the use of DNA probes that allow
the DNA to be identified more easily.
Where can DNA be found?
While there is DNA is nearly every
living cell in a body, most testing is done with
either blood or saliva samples. These tend to yield
the highest concentrations of DNA that can be
sampled and then tested. The most common route is to
take saliva from both the child and each of the
parents and then compare the DNA that is isolated
from those samples.
What is the testing process like?
Scheduling an appointment with a
physician or genetics counselor can start the
process of determining the paternity of a child, in a more formal case, or a test can simply
be performed from the comfort of your own home. In
either case the actual time it takes to obtain the
sample is minimal. Using sterile swabs, the mother,
father, and child will all collect saliva samples
from the inside of their cheeks. The collected
samples are then sent to a paternity testing
laboratory where the samples are run through one or
both of the processes that were previously mentioned
and the DNA markers are established. By identifying
the DNA profile, the lab can then see if there are
enough similarities between the child and the father
in order to establish a clear paternity. The time to
complete the testing once a sample reaches the DNA
testing lab is usually about three days.
A much less common type of test is a
pre-natal paternity test which is performed on
an unborn child. Such a test must be performed in a
sterile medical environment and as such requires a
physician's approval. Because the DNA sample
collection posses a small risk to the unborn child a
physician may recommend against having the test
performed at that time unless there is a good reason
for doing so.
Are at the tests accurate?
Most at home tests can have a
reliability of up to 99% because they employ the
same methods and sampling techniques as a
physician’s office, although care must be taken to
carefully collect the samples and ensure they are
kept sterile. However, as long as the samples are
collected in a controlled manner, at home paternity
testing can have reliability on par with that of
that done in a physician's office setting. Note that in many
cases in order for the test results to be admissible
in court the paternity test must be performed in a
doctor's office in order to ensure the samples were
collected in the proper manner. If court
admissibility of the results is a concern for you,
check with your local municipality to understand
their guidelines.
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