This test is recommended when the persons participating in it are male and female. This type of DNA testing determines the common amount of DNA between both the tested individuals. A sibling DNA test helps in ascertaining that whether the people involved have one common parent, both common parents, or either of the parents in common. This DNA test is dependent on a statistical probability. It is not like a paternity test, but sibling DNA testing doesn’t need to offer any genetic profiles that match with every genetic maker. In this test, the siblingship index is calculated. If the index is less than 1.00, then this signifies non-relatedness. If it is greater than 1.00, then this signifies that they are true full siblings or half siblings.
Sibling DNA Test between Brothers
If the participating siblings are male and wish to discover if they share the same biological father, it is recommended to undergo a different kind of DNA test which is known as a Y chromosome test. This test is deemed to be highly accurate. If the females want to ascertain if they have a common parental line then, they can ask for a direct male blood from a blood-related to take a Y chromosome test on their behalf.
Sibling DNA Test between Sisters
If the participating siblings are female and they wish to discover if they share the same biological father then, it is suggested to go for an X chromosome test. It is important to consider that with the X chromosome testing, their mother’s sample would be needed in situations where the tested females share the same biological mother.
Sample Collection for Sibling DNA Testing
The samples required to undergo the sibling DNA testing are gathered by using the oral swabs. Some companies provide a home kit following the purchase which would usually contain 4 color-coded swabs for each participant. The cotton swabs are supposed to be rubbed inside the mouth, and under the tongue for around 10 seconds, then subjected to dry. The home kits will also include instructions and consent forms. The participants will need to fill the consent forms before returning their samples to the lab. The results are obtained in 7 to 10 working days following the receipt of samples at the lab.
Brothers and Sisters with the Same Mother or the Maternal Line
Brothers and sisters who wish to know that if they are from the same maternal line undergo the DNA test which involves their mitochondrial DNA. This special kind of DNA test is undertaken by both female and male offspring from their mother. But, only females can pass their MtDNA to their offspring. If two or more participants have any common and biological maternal ancestor, then they will have the same MtDNA profile as well. The only disadvantage of this DNA testing is that the result will only let you know that you have a common ancestor or not. It will not tell you the specific ancestor.