Testing the alleged father’s relatives, usually brothers and sisters, is known as an avuncular test and is an alternative means for a paternity DNA test in a scenario where the alleged father is unavailable for testing. An avuncular test is usually the next best option when a grandparentage test is not possible. In an avuncular test, the laboratory will advise sending in the mother’s DNA samples as well. The test will calculate an avuncular index which will tell whether there is a biological relationship between the alleged father’s child and the child’s paternal aunt and/or uncle. The statistical probability will be an inclusion of relationship if it is 80% or higher and an exclusion of relationship should it be 20% or lower.
In the aforementioned scenario where you find yourself needing to determine paternity but the alleged father is not available, there are a number of other options available besides paternity testing or avuncular testing. The alleged father might in fact, have no siblings. In such cases, it might make more sense to carry out a sibling DNA test or even a grandparentage test. With grandparentage testing, if both grand parents are available for the test, then the laboratory can actually reconstruct the missing alleged father’s profile. However, it is essential to have both grandparents. If just one grandparent is available, then ideally one would choose another test such as a DNA test between siblings (to confirm whether or not they have the same dad) or a DNA test between aunts and uncles with their nieces or nephews.
Further information on Avuncular Testing can be found by visiting Aunt-Uncle DNA Testing.