In some instances when people are trying to prove paternity, an alleged parent may be unable or unwilling to participate in the test. In these cases it is possible to perform a DNA sibling test to establish whether siblings have the same parents in common and are full or half siblings.
A DNA sibling test will establish the likelihood of two individuals having the same parents in common. In the absence of an alleged parent a sibling test is the best option to make a direct comparison.
A sibling test will determine whether two individuals are full siblings, half siblings or have no biological relationship at all. By definition, full siblings have two biological parents in common, whereas half siblings will only share one parent.
How The Test Works
The test works by comparing the number of shared genetic markers between the individuals being tested to establish the probability of a biological relationship. The more DNA in common, the greater the probability of a biological relationship.
The laws of genetics are such that true biological siblings can have very different genetic profiles. Some siblings may have taken the same genes from each parent, whereas others may have inherited different genes from each parent, thus making it look like they don’t have much in common.
It is therefore recommended where available to include a parent in a sibling test, as this will improve the interpretation of the results. Normally this would be the mother, and would therefore identify what shared DNA between siblings came from the mother.
The Y-Chromosome Test
The Y-Chromosome test is another method often used when a parent is absent. As long as both the siblings are male, this test will determine whether or not they share the same male gene lineage. Y chromosome is transferred through the direct male lineage whilst the X-chromosome is suitable for female-to-female siblings with the same potential father and different mothers. (Mitochondrial DNA can test both male and female siblings through the maternal lineage).
There are many reasons for using a DNA sibling test, but the most common are:
- Adopted children, or siblings separated at birth, being reunited but with parents absent.
- Siblings with doubts as to the identity of their biological father.
- Legal cases of inheritance claims by individuals claiming to be children of the deceased.
It is important to identify who will be participating in your DNA test, as this will help the laboratory in selecting the best DNA test for you. Always check if permission is required from legal guardians, when dealing with minors, as this will change from country to country.
easyDNA offers a comprehensive range of DNA Paternity Testing services, designed to shed light on most of today’s identity issues. We are here to provide reliable, accurate and confidential DNA Paternity Testing, DNA Relationship Testing and DNA Forensic Testing to both the public and private sector. We operate through a network of offices covering a wide geographic area. We currently operate 12 offices worldwide including Canada, U.S.A, Italy, Belgium, UK, Ireland, Australia, New Zealand, India and South Africa. To contact us with further questions please email info@easydna.net.
