Dear Karen, The triangulation feature is a method that quickly tells you which people are also matching a known relative or a genetic cousin whose relationship to you is unknown. You need to be careful how you interpret the results, particularly when you are dealing with endogamous populations. At this point I would suggest that you not jump to the conclusion that A and B are related to you through the ggg grandfather that you share with your cousin. Perhaps they are related through that line and perhaps not. I think you need data from known first, second, and/or third cousins to help you sort issues like this out. You need to use their data to map your dad's (and your chromosomes) so you can have some idea where each of these segments came from. You can then look at the matches on any one segment and can have better insight as to whether or not they could have come from a specific ancestral line, such as through the ggg grandfather that you share with your cousin. At this point, all I would do if I were you is to enter the data from A and B on your match list and wait for data to accumulate from other matches at 23andMe, Family Finder, and GEDmatch to help you sort out where the genealogical connection is on the segments you share with A and B. Sincerely, Tim Janzen -----Original Message----- From: autosomal-dna-bounces@rootsweb.com [mailto:autosomal-dna-bounces@rootsweb.com] On Behalf Of Karen Hodges Sent: Friday, October 18, 2013 1:42 AM To: autosomal-dna@rootsweb.com Subject: Re: [AUTOSOMAL-DNA] Family finder matches what to make of them Hi Tim My cousin and I match on Chromosome 4. This is my first DNA match besides Dad so I haven't yet needed to map anything.Dad should match my 4th half cousin as it is on his maternal side of the family tree but doesn't. I share a 3G Grandfather with my cousin. I descend from the first wife and they descend from the second. I have contacted Family tree DNA to check that an error has not occurred and it is currently being investigated. I don't see a genealogy connection to my Mum's tree. Match A matches me on chromosome 1 and Match B on chromosome 22 both are listed as 5th to remote cousins. Dad also matches A in the same location as I do on chromosome 1 but does not match B although he does have another match to a person with the same surname. My cousin and I both show match A and B when we triangulate each others name but we don't match them in the same locations. A is also a 5th to remote cousin to my 4th half cousin while B is a 2nd-4th cousin to them. What I need to understand please [with the new tools] if you find a genealogy match with a DNA match [such as my 4th cousin] when you triangulate with their name and find your in common with matches does it mean these other smaller cM matches are related [IBD] because two known related people are matching the same people. eg strengthens the odds that it is not a coincidence? For my cousin match B is 17.15cMs so this should be a relative of hers. but with A we all have smaller matches 8cMs. Karen

Karen In general I agree with Tim. I would add that Triangulation has a very specific requirement: A=B=C=A. That is each pair (AB,AC,BC) must have a shared segment (usually at least 7cM, but perhaps smaller with some risk of a false positive); AND each of these shared segments are significantly overlapping - such that all three - ABC - have, say, at least the same 7cM. You can accept a little less overlap, by accepting a little more risk that it's not right. With so much randomness in atDNA, we cannot guarantee anything. For example the segments themselves are not precise - the end points are often fuzzy. But it works a high percentage of the time. If you are A, and you match B and C on basically the same segment; you still need to determine if B and C share that same segment. This is fairly straightforward using tools at 23andMe or at GEDmatch. At FTDNA the ICW tool indicates if B and C have a shared segment somewhere. Often they share the same place you do, but sometimes they don't. I looked at a lot of these cases a year ago, and - from memory - about 2/3 ICW were on the same segment and 1/3 was not. Or something like that - it was high enough, for me, to investigate more, but not high enough to conclude there was Triangulation - my judgement call. So I usually ask B and C if they match on the same segment we share. Either one can confirm it. This is a simple question for them, and if they are on the same segment with you, this is very powerful information for them, too. Particularly as the Triangulated groups grow beyond 3 folks to 5 to 10 to 20... Such large groups should have enough researchers in them willing to work on place/time matching - clearly if a Common Ancestor doesn't become evident, we are dealing with a brick wall for many. When you have Triangulation, you know the shared segment (among ABC) is on one chromosome, and that the 3 of you will have a Common Ancestor. (Assuming you are one of the ABC). Now if any two in ABC have a known Common Ancestor, there is a good probability that all three of you have the same Common Ancestor. When dealing with deep Colonial roots (and similar populations) the possibility exists that you and a Match could have more than one Common Ancestor. So it's always wise to find at least one more Match who agrees on the genealogy for this segment. This means waiting for additional Matches - but don't worry, they are coming... Jim - Sent from my iPhone - FaceTime! On Oct 19, 2013, at 2:19 AM, "Tim Janzen" <tjanzen@comcast.net> wrote: > Dear Karen, > The triangulation feature is a method that quickly tells you which people > are also matching a known relative or a genetic cousin whose relationship to > you is unknown. You need to be careful how you interpret the results, > particularly when you are dealing with endogamous populations. At this > point I would suggest that you not jump to the conclusion that A and B are > related to you through the ggg grandfather that you share with your cousin. > Perhaps they are related through that line and perhaps not. I think you > need data from known first, second, and/or third cousins to help you sort > issues like this out. You need to use their data to map your dad's (and > your chromosomes) so you can have some idea where each of these segments > came from. You can then look at the matches on any one segment and can have > better insight as to whether or not they could have come from a specific > ancestral line, such as through the ggg grandfather that you share with your > cousin. At this point, all I would do if I were you is to enter the data > from A and B on your match list and wait for data to accumulate from other > matches at 23andMe, Family Finder, and GEDmatch to help you sort out where > the genealogical connection is on the segments you share with A and B. > Sincerely, > Tim Janzen > > -----Original Message----- > From: autosomal-dna-bounces@rootsweb.com > [mailto:autosomal-dna-bounces@rootsweb.com] On Behalf Of Karen Hodges > Sent: Friday, October 18, 2013 1:42 AM > To: autosomal-dna@rootsweb.com > Subject: Re: [AUTOSOMAL-DNA] Family finder matches what to make of them > > Hi Tim > > My cousin and I match on Chromosome 4. This is my first DNA match besides > Dad so I haven't yet needed to map anything.Dad should match my 4th half > cousin as it is on his maternal side of the family tree but doesn't. I > share a 3G Grandfather with my cousin. I descend from the first wife and > they descend from the second. I have contacted Family tree DNA to check > that an error has not occurred and it is currently being investigated. I > don't see a genealogy connection to my Mum's tree. > > Match A matches me on chromosome 1 and Match B on chromosome 22 both are > listed as 5th to remote cousins. Dad also matches A in the same location as > I do on chromosome 1 but does not match B although he does have another > match to a person with the same surname. My cousin and I both show match A > and B when we triangulate each others name but we don't match them in the > same locations. <snip>

Hi Tim Your answer was exactly what I needed to know. I thought it couldn't be so amazing [the new tools although they are wonderful] and your mention of endogamous populations explains the why of how you can match the same people as a known relative but it can still be by coincidence and not related. So the only confident matches for that line are those in the same location as my cousin that we both have in common. Thanks very much Tim Karen On Sat, Oct 19, 2013 at 5:19 PM, Tim Janzen <tjanzen@comcast.net> wrote: > Dear Karen, > The triangulation feature is a method that quickly tells you which people > are also matching a known relative or a genetic cousin whose relationship > to > you is unknown. You need to be careful how you interpret the results, > particularly when you are dealing with endogamous populations. At this > point I would suggest that you not jump to the conclusion that A and B are > related to you through the ggg grandfather that you share with your cousin. > Perhaps they are related through that line and perhaps not. I think you > need data from known first, second, and/or third cousins to help you sort > issues like this out. You need to use their data to map your dad's (and > your chromosomes) so you can have some idea where each of these segments > came from. You can then look at the matches on any one segment and can > have > better insight as to whether or not they could have come from a specific > ancestral line, such as through the ggg grandfather that you share with > your > cousin. At this point, all I would do if I were you is to enter the data > from A and B on your match list and wait for data to accumulate from other > matches at 23andMe, Family Finder, and GEDmatch to help you sort out where > the genealogical connection is on the segments you share with A and B. > Sincerely, > Tim Janzen > > -----Original Message----- > From: autosomal-dna-bounces@rootsweb.com > [mailto:autosomal-dna-bounces@rootsweb.com] On Behalf Of Karen Hodges > Sent: Friday, October 18, 2013 1:42 AM > To: autosomal-dna@rootsweb.com > Subject: Re: [AUTOSOMAL-DNA] Family finder matches what to make of them > > Hi Tim > > My cousin and I match on Chromosome 4. This is my first DNA match besides > Dad so I haven't yet needed to map anything.Dad should match my 4th half > cousin as it is on his maternal side of the family tree but doesn't. I > share a 3G Grandfather with my cousin. I descend from the first wife and > they descend from the second. I have contacted Family tree DNA to check > that an error has not occurred and it is currently being investigated. I > don't see a genealogy connection to my Mum's tree. > > Match A matches me on chromosome 1 and Match B on chromosome 22 both are > listed as 5th to remote cousins. Dad also matches A in the same location as > I do on chromosome 1 but does not match B although he does have another > match to a person with the same surname. My cousin and I both show match A > and B when we triangulate each others name but we don't match them in the > same locations. A is also a 5th to remote cousin to my 4th half cousin > while B is a 2nd-4th cousin to them. > > What I need to understand please [with the new tools] if you find a > genealogy match with a DNA match [such as my 4th cousin] when you > triangulate with their name and find your in common with matches does it > mean these other smaller cM matches are related [IBD] because two known > related people are matching the same people. eg strengthens the odds that > it is not a coincidence? For my cousin match B is 17.15cMs so this should > be a relative of hers. but with A we all have smaller matches 8cMs. > > Karen > > > > ______________________________ > For answers to Frequently Asked Questions about mailing lists, please see: > http://dgmweb.net/MailingListFAQs.html > > > ------------------------------- > To unsubscribe from the list, please send an email to > AUTOSOMAL-DNA-request@rootsweb.com with the word 'unsubscribe' without > the quotes in the subject and the body of the message >