The Grandparents and grandchild DNA test is extremely useful to determine paternity when the father is deceased or not available. The Grandparents DNA profiles contain all the key components of which the alleged father and the grandchild’s DNA is made up of. If both Grandparents are available, this DNA test can be as accurate as the paternity test itself.

Can I test one Grandparent, or is better to test both?

It is possible to carry out either grandparents DNA testing using the samples of both or just 1 grandparent – however, testing just one grandparent can provide inconclusive results which means many companies do not offer it. A serious laboratory would always suggest to test both Grandparents, even though, scientifically speaking it is possible to test just one. With a grandmother or grandfather DNA test, it is highly recommended to include the mother’s sample. Even though some DNA testing companies don’t offer this option anymore, it is a possible to proceed under the condition that it’s the only option available. Including the mother’s sample will help in obtaining a more accurate result. One must keep an open mind that this test could possibly yield a false negative result, meaning that the result indicated that no relationship exists when indeed it does. This occurs as the child would have inherited DNA from the alleged father that originates from the Grandparent that was not tested. For this reason it is always preferred that both Grandparents are submitted for testing. This will enable the laboratory to have a fuller view of the whole picture. A missing persons report outlining the probability of paternity will be issued.

Understanding a Grandparent DNA test result – Missing persons report

In simple terms, each persons DNA profile is composed of two values on each genetic marker. One value comes from the mother, while the other comes from the father. Every genetic marker of the child that contains a value that comes from the father must also be a match with the values present in the DNA profiles of the Grandparents. With a clear view of both DNA profiles of the grandmother and the grandfather the laboratory is able to determine if the child is a match or not. All possible combinations are evaluated and a conclusion is drawn. It is is ultimately possible to determine with accuracy whether the paternity of the missing alleged father is included or excluded. This is called a missing persons report and it is extremely useful in determining paternity when father is deceased.

Grandparent DNA testing – Y Chromosome

If the child being tested is male and only the paternal Grandfather is available for testing, then it would be wise to proceed with a Y Chromosome test. This test is extremely useful in determining if two males come from the same male lineage. Generation after generation, the Y Chromosome is passed from male to male. If a clear direct male lineage is in between the two persons participating in the test. Then it is possible to compare both Y Chromosome profiles in order to determine if they are identical or not. It is important however that there is no involvement of any other male relative in regards to fathering the child as all male descendants of the Grandfather would all carry the same Y Chromosome. With this test it is possible to obtain an accurate result and is also very useful to determine paternity when the father is not available.

DNA testing technology has given the possibility for many other options in order to solve the question of paternity. It is important to consult with an experienced genetic consultant in order to assist in determining the best possible grandparent testing options and if need be to consider better alternatives for your situation.