Grandmother/grandfather test

Grandfather-test (samples of paternal grandfather and grandson)

The grandfather to grandson-test gives information of the direct male lineage – the test is inappropriate if relatives come in question for paternity. 23 markers on the sex chromosome Y are analysed to determine whether or not two male persons descend from the same paternal line to a very high probability.
The average frequency of the genotype in the investigated population group will be indicated.

Grandmother-test (samples of paternal grandmother and granddaughter)

Samples from the paternal grandmother and granddaughter alone are used to clearly determine whether a son of the grandmother is the biological father of the granddaughter.
12 markers on the X-chromosomes are analysed.
This indirect paternity test gives results with the same security as a direct one -  normally the probability reaches more than 99,99% -  under the condition that no other son of the grandmother comes into question as the child's father.