Analysis of the DNA of two separate individuals can provide information as to whether they are full siblings, half siblings, or not related. Please read the information provided below to fully understand the benefits and limitations of the sibship test before ordering.
When a Sibling Test is Required
When the issue of sibship is in question, the recommended method to determine whether individuals are true biological siblings is to test their parents. DNA paternity and maternity testing will always provide conclusive results. However, in situations where the alleged parents are unavailable for testing, a DNA sibling test can be performed to analyze the relationship of biological siblings.
How the Sibling Test Works
When a sibship test is conducted, the DNA laboratory will determine the genetic profiles of the alleged siblings. Based on the type of genetic material inherited by each sibling, a sibship index is determined.
If the sibship index result is less than 1.00, this indicates non-relatedness. If the sibship index is greater than 1.00, this indicates that the two tested individuals are more likely to be true biological siblings. The higher the value of the sibship index, the greater the likelihood that the two individuals are true biological siblings.
To analyze the possibility that the siblings share only one common parent versus two common parents (mother and father), a half sibship index is obtained. The ratio of the half sibship index versus the full sibship index will indicate whether the two individuals are more likely to share only one common parent or two common parents (mother and alleged father).
A Sibling test will help to provide you with an indication of whether you are more likely to be a full sibling, half sibling or not the true biological sibling of the other tested individual.
Increasing the Stringency of the Sibling Test
If there is a known common parent for the siblings (i.e. if you already know that the two siblings share the same mother but wish to determine whether they have the same father), then testing the common parent will greatly increase the accuracy of the sibling test.
Testing more siblings can also increase the accuracy of the test. For example, if two siblings who are definitely related to each other wish to determine if a third person in question is their sibling, then testing the DNA of both of the known siblings against the sibling in question will greatly increase the accuracy of the test and help to determine whether the the sibling in question is related.
What Type of Comparison is Performed?
If two siblings are tested, the test will examine whether they are most likely to full siblings, half siblings, or not related. If more than two siblings are tested, then each sibling will be compared to every other sibling in the test so that you will receive a comprehensive anlaysis of each sibling against every other sibling that is tested.
- Check the status of your test online and download your test report instantly when it is ready
- Results in 3 to 5 business days
What if the individuals to be tested live at different addresses, can you split the kit?
Yes, if the individuals to be tested live in different cities, or even different countries, we can split the kit and send each component to a different address. Since the kits are individually barcoded, the samples will still be tested together even if the are sent back separately. To order a split kit, please write the following into the comments box of the online order form "Please split kit". Please also indicate the name and address to send each component.