DNA testing of other members of the family is known as avuncular testing. Typically, an avuncular test will involves testing the alleged father’s relatives to determine whether they are related to the alleged father’s child. Such a test is suggested when the supposed father is deceased or not available for testing. A result of 80% or higher will be proof of a biological relationship and anything lower than 20% will exclude a biological relationship between the aunt or uncle and their niece or nephew. Ideally, the test would include DNA samples of the paternal aunt and uncle as well as the mother’s and the child. Aunts and uncles share about 25% of their DNA with their niece or nephew. If the participants are males (for example an uncle and his nephew), we would most likely not suggest an avuncular test but a more accurate Y chromosome test.
Essentially avuncular testing will determine whether an aunt or uncle is the biological relative of a child. When a parent is deceased or absent for testing, a standard paternity or maternity DNA test will not be possible. The DNA samples of the uncle and/or aunt are sent alongside that of their niece or nephew and results will be expressed as a percentage. Should the percentage be higher than 80% then that will be sufficient to establish a biological relationship; if it is lower than 20%, then a biological relationship between niece/nephew and their aunt and/or uncle will be excluded. If the mother is available for testing, then is recommended that her DNA samples be sent for testing. Sometimes a DNA test result may show that an aunt or uncle have a very low probability of relationship and this can simply be due to the fact that they share very little common DNA. On the other hand, the two tested parties might have a lot of common DNA between them. Sometimes, two people might actually be biological related but the amount of common DNA can be lower than expected. This is a factor you must consider as a possible outcome to your DNA test when carrying out this type of test. Please visit the following link for further insight into Avuncular Testing.