DNA Testing for Paternity

The Science of DNA Testing for Paternity

DNA testing for paternity uses a method call the Polymerase Chain Reaction (PCR) method. PCR is an extremely effective in analyzing DNA and, as such, can use very small DNA samples. Since your DNA is the same throughout every cell in your body, paternity test results can be determined using DNA samples collected from just about any part of the human body.

PCR also gives scientists the ability to literally create billions of copies of your DNA from just a small sample. To help gather samples to assist in DNA testing for paternity, the DNA paternity testing services from GTL offer buccal and blood collection options. When you submit a buccal sample, our scientists can extract your DNA as a stringlike molecule in order to receive very accurate paternity test results. PCR then generates copies of just a tiny fragment of this molecule, controlling the exact part of the DNA molecule replicated. Once new copies are created, the DNA fragments are analyzed.

DNA testing has numerous applications, but DNA testing for paternity uses 16 different DNA fragments found useful in determining human identity. Each of these fragments is called a locus. In the plural form they are referred to as loci.

Eight fragments, half of a child's DNA profile, will match the fragments from his or her mother's DNA profile. The other eight--the remaining half--will match the fragments from his or her father's DNA profile. If mismatches in the DNA fragments occur when DNA testing for paternity, the alleged father can be excluded, meaning he is not the child's biological father. Naturally then, if the child's fragments match those from the mother and alleged father, the alleged father is not excluded as the child's biological father.

Paternity Test Results

After the GTL conducts DNA testing for paternity, your paternity test results report will show numbers (in the first column) that relate each of the 16 loci used in the DNA test. The GTL DNA paternity test results report provides many pieces of information so it's important to learn how to properly interpret the results of DNA testing for paternity.

Certain columns on the paternity test results page will be marked allele and have numbers showing the two alleles found at each locus. If both alleles are the same size, just one number will be shown.

For example then, if a child has two alleles that are designated 12.3 and 9, and if the mother has alleles 12.3 and 15, the child has inherited the 12.3 allele from the mother. Therefore, the paternity test results indicate that the child must have inherited the 9 allele from the father. In this situation, the 9 allele is known as the obligate paternal allele. The biological father will then be the possessor of the matching obligate paternal allele--9.

When DNA testing for paternity, 15 different loci are examined for matches to the obligate paternal allele, as well as an additional match to confirm the sex of the person providing the sample. If the paternity test results report that the alleged father undergoing DNA testing for paternity does not have the matching allele at each tested locus, he is considered excluded as a biological father. If the paternity test results report that there are matches at each allele, he may be the father. In such cases, another test called a Relationship Index (or Direct Index) for each locus is determined using information that includes the portion of the general male population that possesses the obligate paternal allele at that locus. This index is then reported for each DNA locus tested.

As a final step in DNA testing for paternity, a combined Relationship Index for all of the alleles that were tested is tallied and appears below the chart. This number is what is used to calculate the probability of relationship, (i.e., the likelihood that the man with the alleged father's alleles is indeed the biological parent of the child, as compared to another unrelated man). If the DNA of the alleged father is consistent with the child's, then the paternity test results will conclude that the alleged father is not excluded as the biological father of the child. GTL guarantees accurate and affordable paternity test results, so you can rest assured and relieve some of the stress you may be facing.

DNA Testing for Paternity - Questions?

If you have any questions about our DNA testing for paternity or our paternity test results, or would like to learn more about our DNA test options, please give us a call at (866) 833-6895 today. If you are calling from outside the United States, please direct your inquiries to (575) 646-3465, and our knowledgeable and caring representatives will gladly help you.

Learn more about DNA testing for paternity: Determining Paternity | Paternity Test Kit