Grandfather DNA test is a test to determine the biological relationship between grandfather and grandchild. This test is preferred when alleged father or alleged mother is dead or they are not available to participate in DNA test for some reason. When there is no alleged father for test, parents of him participate in DNA test. Similarly, when there is no alleged mother to participate in DNA test, her parents participate.

One strand of DNA which is composed of two strands is inherited to child from mother whereas the second strand is inherited from father. One of two strands is transmitted to father from grandfather and one of two strands of father (half of it) is also transmitted to child. So, quarter of DNA of grandfather is inherited to grandchild. Since DNA similarity between father and child is more than similarity between grandfather and grandchild, sensitivity of grandfather DNA test is relatively less than paternity DNA test. The situation between grandfather-father-grandchild is also valid for grandfather-mother-grandchild. In order to increase sensitivity, wife of grandfather should definitely participate in test. To sum up, to get more reliable and more sensitive result, if alleged father or mother is not able to test, grandmother, grandfather and grandchild should participate in DNA test. This test can also be performed with samples of just grandfather and grandchild if other individuals are not available. If this is the only option, our laboratory remains at your disposal for grandfather DNA test as always!

When alleged father is not able to participate in DNA test, more precise result can be obtained with Y-STR test if the grandchild is a boy. In humans there are two sex chromosomes as XX in women and XY in men. Each sex chromosomes of child is inherited from each parents. Y chromosome of son is directly transmitted from father without undergoing a change during transfer. Thus, Y-STR test can be preferred to examine possibility of biological relationship from the side of father. This test gives information whether there is father-son, uncle-nephew or grandfather-grandchild relation; however, it does not give information about exact degree of relationship. Also if the person who is not available to participate in DNA test is the mother, Y-STR test cannot be used.

In order to obtain DNA samples to be used in test, several body fluids and materials can be used. Toothbrush, sperm, freshly cut nail, cigarette stub, beverage straw, electric razor, chewed gum, used napkin, urine, sweat, skin, hair root, saliva and blood are some of the body fluids and materials that can be used for DNA test. However, since the yield of isolated DNA is better, mouth swab sample is generally used one.

Our principles are reliability, speediness and privacy. As DNA Hospital, the time required to submit results is just 5 workdays after receiving your mouth swab samples. Before performing tests, we take permissions of test participants and official parents of under 18 years-old children. By using a reference number consisting of numbers and letters, we provide to submit results to only participants, not anyone else.  Moreover, it is possible to check results online by registering to our website!