Can a granddaughter and her grandfather undergo a paternity test?

Generally speaking, a granddaughter and her grandfather can undergo a paternity test, which falls under the category of grandparent-grandchild relationship testing. The detailed explanation is as follows:

Although there is no direct chromosomal genetic relationship between the grandfather and granddaughter, their genetic relationship can be determined through mitochondrial DNA testing and autosomal testing. For example, although a granddaughter's mitochondrial DNA is inherited from her mother, by analyzing specific genetic loci on the autosomes, it is possible to determine to some extent whether a genetic relationship exists between the grandfather and granddaughter.

However, the accuracy of this type of intergenerational paternity testing is somewhat lower compared to standard parent-child paternity testing, because genetic recombination and mutations may occur during transmission, potentially affecting the accuracy of results. When undergoing such testing, it is important to choose a reputable testing institution and collect samples such as blood or oral swabs according to the required procedures.