A grandparents DNA test is a type of relationship test carried out between grandmother, grandfather and grandchild to confirm whether the grandparents tested are the biological grandparents of their grandchild.
A grand-parentage DNA test can be done with the grandfather and grandmother. It can also verify if one or more children belong to the paternal bloodline when the father is no longer available to perform the test or does not wish to participate. Please note that this test only works if both paternal grandparents can participate (grandfather and grandmother).
What answers can a grandparents DNA test provide?
– Biological relationship with the paternal grandfather.
– Paternity Test: The grandfather of the DNA test indirectly allows children to check their biological paternity through the grandfather heritage.
– Biological relationship among siblings (boy and girl): a brother and a sister participating in this test on this occasion will check if they are siblings or half-brothers and half-sisters.
The accuracy of DNA testing paternal grandfather depends on the number of participants.
The classic paternity test with the participation of a father and his child is always better than a test with the paternal grandfather. However in cases where the father’s participation is not possible, a parental test using DNA analysis of the paternal grandfather is a more complex test (hence more expensive) that can reconstruct the genetic profile of the missing father then recalculate the probability that children are biologically related to him.
The result of the DNA test with the paternal grandfather is expressed as a probability of relatedness (percentage). The likelihood can not be known in advance because it depends on the rarity of each of the genetic material, the number of test participants and their degree of kinship. When the father’s mother participates in the test and the test is carried out on 20-23 DNA regions and generally gives a clear result:
Between 0 and 10% probability of parentage: in this case, the probability of relatedness is too low, the test will conclude non parenting, it means that the child is not in the same bloodline as the tested grandparents.
Between 95 and 99% probability, there is a big chance for the people tested to be biologically related. The higher the probability, the greater the certainty that child and paternal grandparents are biologically related. When the paternal grandmother did not participate in the test, it is possible that the probability is only 90%.
When a grandparents DNA test confirmed the biological link between grandchild and her grandfather, the grandchild will have the certainty of being the biologically the child of his father. When the grandparents DNA test excluded the biological link with the grandfather, there will be two cases: either the child is not the son of his father or the father is not the biological son of the tested grandfather.
To maximize the accuracy of the test, it is possible to obtain the participation of other family members, such as:
– Another child of siblings whose paternity is already known.
– The children’s mother: her involvement enhances the accuracy of the results and large laboratories generally treat maternal samples free of charge. In the case of half-siblings, mothers’ participation becomes crucial because the half-siblings share less genetic heritage.
– Uncles or aunts (from the paternal side), their participation can increase the probability of kinship, in special cases, it is even possible to make a different kind of test.
Grand-parentage DNA test conditions:
The test works on the same principle as the full sibling DNA test. The laboratory compares a large number of DNA sequences called loci STR (Short Tandem Repeats) and calculates the amount of common DNA in the test participants: brothers / sisters with their paternal grandfather and paternal grandmother.
The test requires sending oral DNA samples to the laboratory of all participants and their consent forms.
Grand-parentage DNA test results and delivery:
The results of the DNA test with the grandparents are available within 7 days of receipt of samples by the laboratory. Some laboratories offer express processing of your analysis, in exchange for an extra charge, the period is then lowered to 4 or 5 days.