| Can a paternity DNA test be done without the mother’s samples?
Paternity tests done without the mother’s samples are referred to as motherless. Most paternity DNA tests are in fact motherless and the results for such paternity tests are equally accurate. If the alleged father is the biological father of the child, results will show a 99.9% rate of inclusion (if the test is motherless). On the other hand, should the alleged father have played no role in the child’s conception the inclusion rate will be of 0%.
Submitting the mother’s DNA samples is often recommended but not essential to concluding the test. There may however be cases in which having the mother’s sample will give a stronger result (99.99% or higher) and will be required for the test. In some cases a genetic mutation on the father or child’s DNA will result in a slightly lower rate of inclusion for paternity and thus, having the mother samples will help strengthen results.
Can a Paternity DNA test be done without the father’s samples?
Strictly speaking a paternity DNA test must involve the father’s samples or else it would not be called a paternity DNA test; using the same term to encompass other tests that may indicate paternity would be confusing. However, there are DNA tests that can be done without the father’s DNA samples in order to establish paternity. The following are relationship DNA tests that can do the job:
Avuncular DNA testing: this test involves testing the father relatives in order to determine paternity. If the relationship index, for example, between a child and his uncle is high enough, then it is likely that the child’s father is his or her true biological father.
Sibling DNA testing: There are a number of DNA tests that can determine with a high degree of accuracy whether siblings share the same father.
The genetic markers in Paternity testing and the Amelogenin Sex gene
When scientists carry out a DNA test they do no analyze the entire DNA sequence. DNA is far too complex and consists of tens of thousands of genes. Analysts take very specific markers on the DNA samples known as loci (singular Locus). The number of loci tested is important and thus you should look out for accredited laboratories which normally test 15 of these markers. The markers tested will clearly be shown on your results so that you may fully understand how testing is done. An inclusion for paternity means that all 15 markers are matched between father and child. Mismatched markers will results in exclusion.
The Amelogenin sex gene is the 16th marker tested and is the gene which determines sex. Testing this gene is not strictly part of the paternity test but is an important quality assurance measure because:
It ensures that the correct DNA samples have been processes as test participants may have mixed up swabs by placing the father’s DNA swabs in the envelope designated for the mother’s samples. (this is sometimes done deliberately by test participants who hope to alter results)
In very rare cases the father’s DNA samples might turn our as being female. Such a case would warrant some further DNA tests but this inconsistency can only be found if the amelogenin sex gene is tested.
Paternity testing can be done at home using a home DNA testing kit or if one needs to pursue legal matters they can choose a legal paternity DNA test. A legal paternity DNA test differs only in the sample collecting process and must follow what is known as a ‘chain of custody’ which will authenticate all sample and who they came from. Whilst results of a legal test can be used in court, results of a home test cannot. Whichever test you choose, Paternity DNA testing is the only definitive means of resolving paternity issues. |
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