Barton Lewis's Genealogy Pages

Brick wall case study no. 3


In the previous case studies, the matches descended from 2 different children of the most recent common ancestor, with some matches sharing a more recent common ancestor through the MRCA's grand­children. Here, the TG is formed with 2 nearer cousins and their more distant one. This raises the question of how we define a TG when some cousins share a closer relationship than others.

A Smith brick wall


My 3rd great-grandfather, Jasper Smith, was born in Georgia on 3 Mar 1816. We have the exact date from a piece of paper found in the trunk of his daughter in law, Mary Jane (Bell) Smith, after her death in 1936. The paper lists birth dates for Jasper; his wife, Sarah Ann Fletcher, and their children; and death dates for Sarah Ann; some of the children; Sarah Ann’s father, James Fletcher; and Asa Smith.

In the 1860 census, Jasper and his family are listed next to Rebecca Smith and her children, and Ira K Smith and family. Rebecca was Asa’s widow, and the assumption is that Asa was Jasper’s brother. Ira K Smith’s relationship is unknown, but many online trees list him as the son of James H Smith and Elizabeth Poe. James’s probate record lists various heirs without specifying relationships, including Rebecca and Asa Smith’s children. Neither Ira nor Jasper, who had moved out of state, are named.

My uncle, Dewey N Smith, tested his Y-DNA in 2009 and matched no Smiths, or anyone on closer than 12 markers. I uploaded his kit to Ancestry, and he had a strong match with descendants of Ralph Cotton of Stafford County, Virginia – but that is another story. After several years trying to find a direct line male descendant of James H Smth and Elizabeth Poe to test, I did, in 2015. Ira K Smith' great-grandson, Henry Smith, and my uncle were a perfect match.


Probate papers of James H Smith naming Ira and Jasper Smith.

Meanwhile, Rebecca and Asa Smith’s descendant, Diana, discovered more probate files on James H Smith that helped sub­stan­ti­ate that Ira and Jasper were his children. Two entries from 1874 and 1875 show Ira and Jasper relinquishing any claims to James’s estate in return for $125 and $75, paid to them by John N Smith, James’s son and ad­min­istrator of his estate.

At this point, I probably would have been comfortable declaring that Jasper’s parentage was solved, even absent a “smoking gun” document which named him as their child. The 1830 census showed 2 males the ages to be Ira (b. 1823) and Jasper in James and Elizabeth’s household – another piece of corroborating evidence. But with the appearance of some new DNA matches in Family Finder, I found additional evidence for these relationships.


Karen and Patricia are shown above on my mother's Chro­mosome Browser at FTDNA. They have a slight overlap on Chr 15. Paul's segment is at almost the exact same coordinates as Patricia's. He is at gedmatch so is not shown on the FTDNA Chromosome Browser.


Two of these matches were Debbie and Karen. Debbie is a descendant of John N Smith, Jasper and Ira's brother. She matches my mother and uncle on chromosome 5 for 18.5 cM, and on chromosome 7 for 34 cM. Debbie doesn't triangulate with other known Smith or Poe descendants, but her match is sufficiently strong to factor it in as evidence of a connection to this family. Karen is a descendant of Samuel Poe, Elizabeth Poe’s brother. She matches my aunt and uncle for 11 cM on chromosome 3, and my mother for 24 cM on chromosome 15.

While there are a number of strong matches on Karen’s segment, only one, Patricia, has identified Poe ancestry. Karen and Patricia overlap for a small portion of their segments with my mother. Paul, who is a match at gedmatch (and so not showing in the FTDNA Chromosome Browser), overlaps with Patricia at almost the exact same coordinates.

Excluding the small overlap with Karen, Patricia and Paul, the only TG consists of my mother, Patricia and Paul. Patricia and Paul are more closely related than the other matches. Their closer relationship means they could be sharing DNA with each other through another of their common lines, and my mother may just possibly share another, undetected common ancestor with them that is responsible for the match.


In situations where there is a most recent com­mon ancestor for everyone and a more recent com­mon ancestor for some of the match­es, the pos­si­bilities for an alternative route through the in­ter­ven­ing generations are increased. Lydia’s fa­ther or William A ("Archie’s") mother or one of his other grandparents could have passed the segment. Arch­ie’s pedigree shows that exactly half of his great-great-grand­par­ents are unknown. While one would expect if the common ancestor were another couple at the same level as Stephen and Mary Poe that the surname would be recognizable in the matches’ trees, two of these surnames are missing from Archie’s tree. If the CA were pushed back one generation further, then the possibilities are greatly compounded that there is an alternative pathway for the segment other than the known connection.


This example points up the problems when our matches do not each descend from a different child of the distant MRCA. Indeed, this is rarely the case. There is usually a nearer MRCA for some - even if it's one generation closer - or several generations, as here. We shouldn't toss out such TG's, but rather weigh all the evidence, including other DNA evidence. Because I know (completely independently of the matches here) that my kits are matching on each of the chromosomes in this example on a segment they got from their grandfather, Archie, I am confident that their connection to all the matches discussed here is through James H Smith and Elizabeth Poe; and since there is an overlap with the more closely related matches, Patricia and Paul, and Karen - albeit a small one (the Rutgers Map Interpolator calculates it a just over 9 cM) - the possibility that my Kits and Patricia and Paul are sharing the segment through some other line than Poe is smaller than it would be otherwise.

The other thing I like about this example is how the documentary and DNA evidence are mutually reinforcing. We sometimes forget how important a paper trail is to corroborating the things we see - or think we see - in a match. To illustrate this, for my next case study, I have chosen a TG which looks good on paper, but for which the lack of any paper trail leaves us none the wiser.

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