Ok, so I have a match on chromosome 22 between my father and a known descendant of a common ancestor on chromosome 22 from position 15492342 to 20645312 for a total of 10 cM. Their relationship is distant, but identified. They share a common gr gr grandfather, although through different wives. They also have a common surname and both test into the same group of the DNA surname study. So do I understand that this position cited above can be determined to have come from that common gr gr grandfather and can be assigned to him at this point? Janis Walker Gilmore (just beginning the learning curve, but obsessed with it)