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Frequently
Asked Questions About DNA / Paternity Testing
1. What is DNA testing?
2. How accurate is it?
3. How old does the child have to be before they can
be tested?
4. Does the mother have to be present for the test
to take place?
5. What kind of samples do you take?
6. How does the paternity test work?
7. What do the results mean?
1.
What is DNA testing?
DNA paternity testing uses the DNA (deoxribonucleic acid) genetic
material in the cells of your body to determine parentage. At the
moment of conception, the 23 chromosomes present in the woman's
egg and the 23 chromosomes present in the man's sperm combine to
give a total of 46 chromosomes to the child. These 46 chromosomes
are presents in every cell of your body. Thus, every parent has
given their child 23 of their own chromosomes, and this is what
DNA testing tests for.
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2.
How accurate is it?
A DNA paternity test is the most accurate form of paternity testing
currently available. If the DNA patterns of the mother, child, and
alleged father match on every DNA probe, then the probability of
paternity is 99.9% or greater. This means that the man is "practically
proven" to be the father of the child.
If the DNA patterns between the child and the alleged father do
not match on two or more DNA probes, then the man is 100% excluded
and has a 0% probability of being the child's father.
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3.
How old does the child have to be before he/she can be tested?
Children can be tested for paternity even before they are born,
so there is no age limit on when a paternity test can be done. DNA
testing can be performed on a very small blood sample (about 1/4
to 1/2 a teaspoon) or a moth swab (buccal swab), so newborns and
infants can be easily tested. To test paternity before birth requires
that Chorionic Villi Sampling (CVS) or Amniocentesis be performed
to gather appropriate cells.
DNA testing can also be performed post-mortem by collecting specimens
at the coroner's office.
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4.
Does the mother have to be present for the test to take place?
No. The DNA paternity test can be performed even when the mother
is not available. If the DNA probe patterns between the alleged
father and child do not match, then the man is still 100% excluded
from being the biological father of the child. If the patterns match,
the the probability is 99% or greater that the man is the father.
The person who brings the child in for testing must provide proper
identification for the child.
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5.
What kind of samples do you take?
Paternity testing can take place from a wide variety of cells, including
blood samples, cheek cells, tissue samples, and semen. Each test
provides the same accuracy, due to the presence of DNA material
in every cell of the body.
To get the buccal swab (mouth swab), a buccal swab is used to gently
massage the inside of the child's or adult's mouth to gather the
cells.
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6.
How does the paternity test work?
DNA is taken from the sample or blood, cheek cells, or cultured
cells. Enzymes are used to cut the DNA sample in fragments which
are placed into a gel matrix. An electric current is used to drive
the fragments across the gel, making the smallest fragments move
the farthest and the larger fragments move the shortest distance.
The separated DNA fragments are transferred to a nylon membrane.
This membrane is exposed to a labeled DNA probe (a short piece of
customized DNA that recognizes and binds to a unique segment of
the tested person's DNA). The nylon membrane is then placed against
a film which, after it is developed, reveals black bands where the
probes are bound to the DNA. The child's visible band pattern is
unique, with half matching the mother and half matching the father.
The process is repeated several times with different probes, each
identifying a different DNA area and producing a distinct pattern.
Using several probes creates a greater than 99.9% certainty about
paternity or identity.
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7.
What do the results mean?
The DNA paternity testing results show conclusively whether the
alleged father is the biological father or not. He is either included
by greater 99.9%, or excluded by 100%.
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