In This Article
In This Article
DNA testing is a helpful tool in identifying blood relatives. The results are usually more accurate when the people being tested have closer relations.
For example, it’s easier to identify a mother or father than to pin down an uncle, aunt, cousin, or grandparent.
This is why paternity testing is the best option for proving a child’s father. But if the father is unavailable, establishing an aunt or uncle relationship may help confirm paternity.
We asked Dr. Rizza Mira to share her insights on avuncular testing.
An aunt or uncle DNA test or an avuncular DNA test is performed in place of a paternity test.
It is used when paternity needs to be confirmed, but the alleged child’s father is not available for testing.
The alleged father’s siblings can take his place during an avuncular test. It can determine paternity since siblings share 50% of their DNA.1
Dr. Mira says that a child shares roughly 25% of their genes with an uncle, but only if he is a full brother of the alleged father.
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The following people are usually required to take an aunt/uncle DNA test:
Some DNA testing companies always include the child’s mother in the process. The mother’s genetic markers can help geneticists reach conclusive results.
“Testing the mother ensures elimination of the similar genes acquired from the mother.”
For better accuracy, it’s also best if more than one sibling takes the test.
If the child and the alleged father’s sibling are biologically male, experts may perform a Y-chromosome DNA test for better accuracy.
This test is called Y-chromosomal short tandem repeat polymorphisms (Y-STR).
Fathers pass down their Y-chromosomes to their sons unchanged. Brothers will share the same Y-DNA from a common biological father.
A Y-STR test can tell if a male child and his alleged uncle share the same Y-DNA. It confirms that they are true biological relatives from the paternal side.2
First, the lab experts will test DNA samples for a polymerase chain reaction (PCR). This process magnifies specific regions of the DNA and examines them for patterns.
DNA patterns from the aunt or uncle’s samples are compared with the child and the biological mother.
The testing company will then generate a statistical analysis of genetic matches between the alleged aunt and niece or the uncle and nephew.
Next, the laboratory evaluates the gathered DNA samples from each subject and establishes a genetic profile. Genetic profiles are analyzed using a kinship index.
A kinship index score of more than 1 suggests the subjects are likely to be related. Higher kinship index scores may indicate a closer biological relationship.
Avuncular DNA tests use the same testing method as other DNA tests. DNA samples are collected from the insides of the cheek using a buccal swab.
The swab gently scrapes off cells from the mouth. You can collect the sample at home (with a self-collection kit) or with the help of a doctor.
Samples will be collected from each participant and sent to a laboratory for DNA analysis. The process usually takes a few days to a week. It depends on the testing company and its partner laboratory.
Siblings share 50% of their father’s DNA.
An aunt/uncle test can help confirm paternity if the suspected father is absent. It can be useful when the child’s father is dead, missing, or unavailable for the test.
A child only shares 25% of their DNA with their father’s siblings.
As a result, an avuncular can’t confirm a child’s biological relationship with an uncle or aunt. But it can tell if someone is likely to be their uncle or aunt.
Sometimes, a child may have the same genetic information as their biological father and their uncle and/or aunt. It is a rare condition known as congenital chimerism.3
Human chimerism is a genetic mutation that causes a person to have two or more sets of DNA.
A chimera child who undergoes aunt/uncle DNA testing may return false positive results. Further tests are needed to prove a child’s paternity in these cases.
A private test may be enough if you want to confirm paternity for your personal knowledge or peace of mind. You can take these tests from the comfort of your home.
Legal avuncular DNA testing is usually done in a hospital or clinic. However, some at-home DNA tests can give you court-admissible results.
Legal avuncular tests meet specific requirements. For example, they may:
These ensure that the collected samples belong to the same people in the report. It prevents them from manipulating avuncular test results in their favor.
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