Wesley, please be aware that in method no 1 not matching doesn't automatically mean anything. Especially with several generations relationships the corresponding ancestral segment might be too small to be detect by the DTC's. So it's not a general rule which might mislead other people. In your case you should indeed find a large enough segment (actually several along different chromosome) Andreas > On 21 Nov 2015, at 16:58, Wesley) Johnston via <genealogy-dna@rootsweb.com> wrote: > > Thanks very much for your responses on this. This has allowed me to see two different ways forward on this. > 1 - Elizabeth and Tim's method - Find descendants of Mary's husband Joe's siblings who are willing to test and see if they match Sam's son. If they do, the Sam's mother is one of the daughters of Joe and Mary. If they do not match, then it is evidence for Mary being Sam's mother (although we would really need to test several people and have them all not match in order to be sure it was not some fluke of atDNA inheritance). > 2 - Belinda's method - See what the existing cousins' level of relationship is to Sam's son in terms of shared DNA, maybe identifying and testing a few other relatives who could shed more light on this. > I am going to try method 2 first, since we have 7 relatives on Sam's mother's side who have already tested. So we might have enough to make a preliminary determination that way. But I ultimately see that method 1 is something we have to eventually do. > Wesley > > > ------------------------------- > To unsubscribe from the list, please send an email to GENEALOGY-DNA-request@rootsweb.com with the word 'unsubscribe' without the quotes in the subject and the body of the message

I want to share what I found out in a first step toward method 2 below. I generated a GEDMatch generations matrix for Sam's son and six of his documented cousins who have tested (closest of whom is either a 1st cousin once removed or 2nd cousin, depending on who was the mother of Sam's father -- and most distant of whom is either a 2nd, 2x or a 1st, 3x). It turned out to be a calibration of the GEDMatch generations matrix against the two forms of the actual generations matrix (one form for Mary as the mother of Sam and one form for Mary's daughter as the mother). It clearly showed how wide the normal natural variability can be even in close generations: two siblings showed as 1.3 generations to MRCA for example. And one pair (the most distant one) known to be actual MRCA 4.5 was estimated by GEDMatch at 7.2 -- WAY OFF. So it is clear that in-generation variability even within one generation already was off and that as the relationships became more distant, the range of variation widened rapidly, resulting in the very large error noted above. And the bottom line for our effort to identify Sam's mother is that it simply cannot be done from the cases we have. This became extremely obvious in comparing how two siblings (who are either Sam's son's 1st cousins 2x removed or 2nd cousins 1x removed) were estimated in comparison of Sam's son's closest cousin in the group. One of the siblings was estimated by GEDMatch to be exactly the same (3.5) for both Sam's son and Sam's son's closest cousin, which would indicate that Mary's daughter was Sam's mother. But the other sibling was estimated by GEDMatch to be exactly a half generation apart for the same pairings (3.2 and 3.7), which would indicate that Mary was Sam's mother. So two siblings' estimates resulted in exactly opposite conclusions. And it was entirely due to the normal range of variation of inherited DNA. So the bottom line is that the GEDMatch generations matrix alone does not suffice with the currently tested six cousins: it does not tell us who Sam's mother was. So we now have to start identifying key people to test, both for method 2 and for method 1. On 21 Nov 2015, at 16:58, Wesley) Johnston via <genealogy-dna@rootsweb.com> wrote: Thanks very much for your responses on this. This has allowed me to see two different ways forward on this. 1 - Elizabeth and Tim's method - Find descendants of Mary's husband Joe's siblings who are willing to test and see if they match Sam's son. If they do, the Sam's mother is one of the daughters of Joe and Mary. If they do not match, then it is evidence for Mary being Sam's mother (although we would really need to test several people and have them all not match in order to be sure it was not some fluke of atDNA inheritance). 2 - Belinda's method - See what the existing cousins' level of relationship is to Sam's son in terms of shared DNA, maybe identifying and testing a few other relatives who could shed more light on this. I am going to try method 2 first, since we have 7 relatives on Sam's mother's side who have already tested. So we might have enough to make a preliminary determination that way. But I ultimately see that method 1 is something we have to eventually do.     Wesley

Wesley, What are the cM's they share with each other and the suspected generations/family relationships? With Blaine's table and other available averages for genetic distance there might be some clue (all calculated given the standard settings at Gedmatch). Andreas > On Nov 23, 2015, at 00:49, Wesley Johnston via <genealogy-dna@rootsweb.com> wrote: > > I want to share what I found out in a first step toward method 2 below. > I generated a GEDMatch generations matrix for Sam's son and six of his documented cousins who have tested (closest of whom is either a 1st cousin once removed or 2nd cousin, depending on who was the mother of Sam's father -- and most distant of whom is either a 2nd, 2x or a 1st, 3x). > It turned out to be a calibration of the GEDMatch generations matrix against the two forms of the actual generations matrix (one form for Mary as the mother of Sam and one form for Mary's daughter as the mother). It clearly showed how wide the normal natural variability can be even in close generations: two siblings showed as 1.3 generations to MRCA for example. And one pair (the most distant one) known to be actual MRCA 4.5 was estimated by GEDMatch at 7.2 -- WAY OFF. > So it is clear that in-generation variability even within one generation already was off and that as the relationships became more distant, the range of variation widened rapidly, resulting in the very large error noted above. > And the bottom line for our effort to identify Sam's mother is that it simply cannot be done from the cases we have. > This became extremely obvious in comparing how two siblings (who are either Sam's son's 1st cousins 2x removed or 2nd cousins 1x removed) were estimated in comparison of Sam's son's closest cousin in the group. One of the siblings was estimated by GEDMatch to be exactly the same (3.5) for both Sam's son and Sam's son's closest cousin, which would indicate that Mary's daughter was Sam's mother. But the other sibling was estimated by GEDMatch to be exactly a half generation apart for the same pairings (3.2 and 3.7), which would indicate that Mary was Sam's mother. > So two siblings' estimates resulted in exactly opposite conclusions. And it was entirely due to the normal range of variation of inherited DNA. > So the bottom line is that the GEDMatch generations matrix alone does not suffice with the currently tested six cousins: it does not tell us who Sam's mother was. > So we now have to start identifying key people to test, both for method 2 and for method 1. > On 21 Nov 2015, at 16:58, Wesley) Johnston via <genealogy-dna@rootsweb.com> wrote: > > > > Thanks very much for your responses on this. This has allowed me to see two different ways forward on this. > 1 - Elizabeth and Tim's method - Find descendants of Mary's husband Joe's siblings who are willing to test and see if they match Sam's son. If they do, the Sam's mother is one of the daughters of Joe and Mary. If they do not match, then it is evidence for Mary being Sam's mother (although we would really need to test several people and have them all not match in order to be sure it was not some fluke of atDNA inheritance). > 2 - Belinda's method - See what the existing cousins' level of relationship is to Sam's son in terms of shared DNA, maybe identifying and testing a few other relatives who could shed more light on this. > I am going to try method 2 first, since we have 7 relatives on Sam's mother's side who have already tested. So we might have enough to make a preliminary determination that way. But I ultimately see that method 1 is something we have to eventually do. > Wesley > > > ------------------------------- > To unsubscribe from the list, please send an email to GENEALOGY-DNA-request@rootsweb.com with the word 'unsubscribe' without the quotes in the subject and the body of the message