Sibling DNA Testing

dna photoSibling DNA tests can be used to determine if two people are full or half siblings by analyzing tissue samples from both individuals. This is generally used when the sibling’s father is not available for paternity DNA testing and they want to prove relationship to one another.

There are two types of sibling DNA tests that can be conducted. Half siblingship tests are conducted when the two people suspect they share one biological parent but not the other. A full siblingship test is conducted when they share one biological parent and want to confirm that the other parent is the same for both siblings.

dna photo

Brother and sister DNA test

Samples are collected using a pain-free buccal swab technique. Similar to a common cotton swab, the buccal swab is rubbed on the inside of the mouth to collect soft tissue and saliva before being deposited into a sterile container. The containers are marked and recorded with the all the pertinent information. Once the samples have been collected and the consent forms are completed, they are sent to the laboratory for analysis.

When submitting samples there will be different procedures based on the reason for testing. If the sibling DNA test is being done by two consenting parties for peace of mind, the process is fairly straightforward and the procedure is not as stringent as if it is being used for legal purposes. If the DNA test is being used to satisfy a matter before the court, stricter procedures will be in place to ensure the proper chain of custody is followed and that the results can be legally defensible in court.

What happens after the sibling dna test?

Once the DNA is analyzed, a report will be generated and provide a “Combined Siblingship Index” that can be used to determine whether the genetic odds are in favour or against a sibling relationship. A sibling DNA test is one of the most complex tests conducted for biological linking so is sometimes not as conclusive as a paternity or maternity test. The easiest sibling test that can be conducted is by two male individuals looking to confirm the share the same father as the Y chromosome is directly passed from father to son.