Segment Triangulation vs Tree Triangulation? Chance?

[MoberlyDrake]

Since I tested way back in 2010, most of the talk on this board has been about the importance of segment triangulation, but I've been hearing a lot about tree triangulation lately. How reliable is tree triangulation? Ancestry puts a lot of stress on it, but I assumed it was because they were too greedy to put any money into designing and maintaining a chromosome browser.

I have a case here where my mother has both with a couple she cannot possibly be descended from!

John Bryan m. Sarah E. Bucy around 1803 in Rowan Co., NC and moved to Coffee Co., TN
Among their children were:

David Barton Bryan
John Morgan Bryan
Joseph Bryan
Marquis LaFayette Bryan

At FTDNA:

Match A - a descendant of Marquis LaFayette Bryan (her 8th closest match after family members)
Total 66 cM, longest segment 33.16 cM on chromosome 7 from 2,890 to 22,231,142

Match B - a descendant of David Barton Bryan
Total 21 cM, longest segment 9.74 cM on chromosome 7 from 15,056,977 to 21,763,530

John Bryan was the great-grandson of Morgan Bryan an Martha Strode:

Match C - a descendant of Joane Strode m. Thomas Mendenhall, whose ancestors came from an area of England where the ancestors of Martha Stode owned property. Common ancestors very likely, but perhaps as far back as the 1400s or 1500s. Match C is on the "In common with" list of both Match A and B, but I have no idea what segments he shares with them. With my mother he shares a total of 49.3 cM, longest segment 8.46 cM on chromosome 7 from 86,892,272 to 94,965,170

At Ancestry.com my mother has:

Match D - a descendant of John Morgan Bryan - 26.7 cM across 2 segments

Match E - a descendant of John Morgan Bryan - 24.6 cM across 1 segment
Two other family members tested : one 15.8 cM across 1 segment, the other 7.7 cM across 1 segment

Match F - a descendant of John Morgan Bryan - 21.0 cM across 1 segment

Match G - a descendant of John Morgan Bryan - 14.4 cM across 1 segment

Match H - a descendant of Joseph Bryan - 10.4 cM across 1 segment

One other match at Ancestry probably, going by surname and shared matches. (14.2 cM)

Almost all of these matches are on each other's shared match lists.

She also has a few matches at Ancestry who are descendants of sisters of this John Bryan, with segments ranging from 15.2 to 6.5 cM.

3 out of 4 of my mother's grandparents were recent French and German immigrants. One grandparent had colonial American ancestors, half of them from NJ and the other half probably from NC and VA. I don't see how she could have all these matches to one nuclear family, apparently of UK origins, by sheer chance.

But John Bryan lived in the wrong place and time to be a direct ancestor. He left a Bible record and there is a family cemetery and good county records. Since my mother cannot be descended from John Bryan, what is the likelihood that she is descended from a sibling or a cousin of John Bryan??? My mother has no Bucy (Bucie, Busey, etc. matches). I checked out that possibility . . .

Can you have that many matches descended from one family and NOT be related somehow??? I don't consider 1800 that far back, genealogically speaking.

[John McCoy]

I have a feeling some Bryan/Bryant researchers have hooked up with the well-known Morgan Bryan family in error. From personal research experience (for my Bryant family, Virginia, Tennessee, Kentucky, and Indiana), there seem to be Bryan/Bryant families all over the place, too many for all of them to be descendants of Morgan. If that is the source of the confusion, there's a lot of work to be done to untangle it. Genetic evidence (Y DNA and autosomal DNA) needs to be sought to confirm or reject the proposed relationships.

[MoberlyDrake]

Whether or not this John Bryan in Coffee Co. TN was or was not a descendant of Morgan Bryan, I don't know, do you know? The information online is confusing. But it is irrelevant to the question of why my mother has such an extraordinary number of matches who are descendants of this particular John Bryan's children, considering her ancestry.

[T E Peterman]

I think tree triangulation could be very misleading. Some trees are junk. Moreover, if you happen to share a couple of ancestors on your tree with one of your matches, it doesn't mean that its the source of DNA.

Segment triangulation needs to rule the roost. I recommend using Genome Mate Pro (a free download). I also recommend testing a field of cousins with Family Finder, so that you can really ascertain side of family.

Timothy Peterman

[Biblioteque]

Paper can be wrong and trees can be wrong, but DNA does not lie.

As Timothy said, if you have multiple tree matches, how are you going to know which one it is without segment matching. The dna match could possibly be behind a brick wall, or not even in your tree yet.

Without doing a one-to-one comparison at Gedmatch you cannot determine if each person matches each other person in a TG which is essential. An ICW is helpful, but does not help you prove the segment match. GEDmatch and one-to-one are the operative words.

DNA does not lie, but you do have to know how to interpret it.

[georgian1950]

Paper can be wrong and trees can be wrong, but DNA does not lie.

As Timothy said, if you have multiple tree matches, how are you going to know which one it is without segment matching. The dna match could possibly be behind a brick wall, or not even in your tree yet.

Without doing a one-to-one comparison at Gedmatch you cannot determine if each person matches each other person in a TG which is essential. An ICW is helpful, but does not help you prove the segment match. GEDmatch and one-to-one are the operative words.

DNA does not lie, but you do have to know how to interpret it.

Thank you Marietta. I agree completely, though I would add one thing. Our arbitrary parameters keeps us from seeing a match which is really there. Some people might say that we already have too many false-positives. I have found that false-positives are not really what people think they are. In almost all cases they match a piece of a common ancestor's auDNA, but it is built up by both parents having lines back to the common ancestor. The real problem is figuring out whether matching segments (even small ones) are independent of the common ancestor.

Jack Wyatt

[Biblioteque]

Thank you, Jack. Along those lines, may I add one point from my experiences. Nowhere have I heard this espoused, but it makes common sense. And, I have an example from a new match this morning at Ancestry.

Cheri and I have a 6.4 cMs segment tree match, and the CA was born 1686. (Yes, Ancestry even flagged it). Since Cheri is a generation younger than I, I asked if she would have her father tested since he and I would be closer to the same generational level; and he could possibly share ~12cMs with me, since Cheri quite likely went through re-combination. But we know, Dna is random and re-combination does not always happen.

Since I am sometimes a generation or two older than some of my matches, I always try to find out the age of the donor dna (if we are sharing cMs below the usual threshold) so I can put it in the perspective of a level playing field. Guess this is a form of "tweaking".

This just makes common sense to me.

[MoberlyDrake]

I noticed this apparent Bryan connection a few years ago and I'm certainly not jumping to conclusions. Actually I'm rather afraid of claiming anything based on DNA matches, except for obvious close cousins.

But since it has started looking likely, every time I get a Bryan match with a tree back enough generations for there to be records online, I find records myself to verify every step back to the Bryan ancestor. This is time-consuming, but at least I know if their trees are correct. You often have to accept that matches know who their parents or grandparents are because sometimes you can't get recent records online. This is the case with the match I said was probable. She has her mother's full name and only her father's surname, and I couldn't prove anything. But when you get back into the 1700s in Rowan Co., NC, records are scarce and not clear.

There has been something of a new development since I posted. I have been in contact with a match here, who triangulates with Match A. This lady shares a total of 72.39 cM, longest segment 24.2 on chromosome 7 from 2,890,110 to 16,641,159 with my mother. She does not know of any Bryan ancestor, but does have a lot of Rowan Co., NC ancestry. She has also tested at Ancestry where in addition to my mother, she matches D (26.7 cM), one of E's family members (15.8 cM) and here she shares 33.6 with match A. I may have to try researching her tree.

[MoberlyDrake]

I have been doing traditional genealogy for almost 20 years, using primary documents, not copying silly online trees. In many cases I have gone back to 1600 or earlier. In some only into the 1700s and in two cases I'm stuck with people born about 1810 in KY. I have also tested several family members.

I just don't see any way this Bryan family in TN could be related to any of Mom's 3 German and French immigrant grandparents. There's not much chance of a connection with her NJ line either, though there is always the possibility of some colonial or English connection somewhere way back.

[PDHOTLEN]

The surname Ryan looks to be high in the social totem pole. I was recently following an offshoot line that is supposed to end up at Queen Elizabeth II. This line is not straight, but jumps between siblings here and there. A daddy to two of those sibling sons, Edward Harley III, is given as born at Brampton Ryan in Herefordshire in 1699. One Harley son went to colonial Virginia, while the other inherited the estate back in England. Maybe the Ryan name also came over to Virginia back then?

Oops, sorry! I thought this thread was about Ryan (instead of Bryan).

[MoberlyDrake]

One other match at Ancestry probably, going by surname and shared matches. (14.2 cM)

I just started working with this match. She had her married name, her father's surname and place of death (Michigan) and her mother's given name, maiden name, place and dates of birth and death. That was all, but the surname of the father was Matthews and I knew that John Alexander Bryan had a daughter who married a Matthews. The hardest part was finding her mother's obit. It turned out she had remarried and even when I found it, it didn't provide me with her first husband's given name. But it did give me her children's names. Looking at the dates, I wondered if any of her children had died after she did. I quickly found an obit for one of them and it gave his father's name. I found the father's obit, giving his place of birth as Coffee Co., TN. In no time I proved the line back to John Alexander Bryan, son of John Bryan and Sarah Bucy.

Some of my DNA matches would be amazed at the trees I have for them when they don't have a clue as to who their own grandparents were! It's a pity I can't break down my own brick wall!

Online obituaries are a wonderful resource when you can find them.