Grandmother & Grandfather DNA testing: determining paternity without father

One of the most popular ways of determining paternity without the father is through a Grandmother and grandfather DNA test. The parents of the alleged father can play an important role in determining paternity by submitting their own DNA instead of the alleged father’s. This is especially useful when the father is not available. It can in most cases be used to as a paternity test if father is deceased.

Will I need both Grandparents, or is only one enough?

It is scientifically possibly to carry out a Grandparent DNA test with either one or both Grandparents but a serious laboratory would always suggest that you include both Grandparents. In the case where only one Grandparent is only available, it is highly suggested that the mother’s sample is included in order to identify the parts of the DNA of the child have originated from the mother, leaving only the paternal parts to be compared against the DNA of the Grandparent. Like any other relationship test, the grandparent test, is based on a statistical analyses of the DNA profiles of the Child and the Grandparents. The only problem that one is faced when carrying out a Grandparent test with only one Grandparent is that there is a possibility that the test yields a false negative. In other words, it’s possible that the result states the there is no biological relationship with the Grandparent and the grandchild when indeed there is. That is why it is always preferred that two both Grandparents are submitted for testing as in this case it would be possible to issue a missing persons report.

Grandparent DNA test result – Missing persons report

Most of you might easily understand that a child’s DNA is formed of genetic markers that have originated from both his mother and father. In the same logic it is also understandable that in every genetic marker of the grandchild’s DNA, one value must also match with either a genetic marker of the grandmother or the grandfather since the value in the genetic marker of the grandchild that has originated from the father originally originated from the Grandmother or Grandfather. It is therefore possible to produce, out of the Grandparent’s DNA profiles, all possible combinations of DNA profiles to see if one could possibly match with that of the Grandchild. In this manner it is ultimately possible to determine with accuracy result the could either include or exclude the paternity of a possible child of the grandparent as the father of the grandchild. This is called a missing persons report and it is extremely useful in determining paternity when father is deceased.

Y Chromosome testing with a Grandparent

If only the Grandfather is available and he happens to be the Paternal Grandfather of a male Grandchild, then the best option for testing would be the Y Chromosome test. The Y Chromosome is passed on, generation after generation, from one male relative to the other. Since there is a direct male line descending from the Grandfather to the Grandchild, it is more useful to test the Y chromosome to check if they match or not. This type of test can give an extremely accurate result and is also very useful to determine paternity when the father is not available.

Before giving up, thinking that there is no hope in determining paternity if the father is not available, it is always good to speak to a professional genetic consultant who can properly guide you to your best possible option to assist you clearing your doubts.