BackgroundAll living persons and test subjects have been anonymized for privacy reasons. In this particular study, AncestryDNA performed all DNA tests. Abstract

A client took an AncestryDNA test to investigate the pedigree of their Great-Grandmother. The outcome was not as anticipated!

Introduction Our client's Great-grandfather, Samuel Albert Thompson ostensibly had eight children by two wives: five children by his first wife and three by the second.

Our client (MS) reported that little was known about wife #1, from whom the client was descended: no photographs, few primary sources, and no death record. The client reported that their grandfather said that little was spoken about his mother, Jennie Telfer, and no one living appeared to have any idea as to the circumstances of her death or what precisely happened in this regard. Discovering New Ancestors was engaged to investigate as best we could, using traditional research methods and the results of the client's AncestryDNA test. The client's DNA matches suggested that four direct descendants of Samuel Albert Thompson had already tested: two Grandchildren of Samuel Thompson (AT and DT) and two Great-grandchildren (RB and MS):

As subject RB is descended from Samuel's second wife, he would appear to be a half-relation to the DNA test-takers descended from Samuel Thompson and his first wife. This would suggest that one strategy would be to use our CMA process to curate a set of In Common With DNA matches shared by AT, MS, and DT and then to exclude from this collection matches shared with RB, presumably leaving a collection of siginificant DNA matches connected to our client through the ancestors of Samuel Thompson's first wife.

Preliminary Analysis of Shared Linkage

Whilst downloading the full sets of DNA matches required by CMA, it seemed reasonable to examine the amounts of DNA shared by our test subjects, as shown in the accompanying table:

We began our analysis with RB and MS — the two Great-grandchildren of Samuel Thompson by different wives — whom we would expect to be half-2nd cousins. However, (per the Shared cM Project) the 371cM of DNA shared by RB and MS significantly exceeds the amount of DNA half-2nd cousins would be expected to have in common, suggesting that RB and MS are actually full-2nd cousins, sharing 2 Great-grandparents. Since RB's grandmother was born 7 years after the last of Samuel Thompson's children by his first wife, it's reasonable to conjecture that MS's grandfather was also born of Samuel Thompson's 2nd wife, the fact that his middle initial (T) stood for Telfer, the family name of Samuel's first wife.

If RB and MS are full-2nd cousins, — presumably ahring Samuel Thompson and his 2nd wife as common Great-grandparents — then we would expect that DT would no longer be MS' first-cousin once removed, but would rather be a half-1C1R. However, the 514cM of DNA shared by MS and DT are well beyond the reported limits of the half-1C1R relationship.

Finally, we turn to DT and AT, the two tested grandchildren of Samuel Thompson and his first wife. We've already established that DT, MS, and RB are all full-relations, sharing both Samuel Thompson and (presumably) his 2nd wife. If DT and AT are full-first cousins, then all of our tested subjects are descended from Samuel Thompson and the same wife; otherwise, a half-cousin relationship between DT and AT would indicate that AT is indeed descended from Samuel Thompson and wife #1, while our other subjects are descended frm Samuel Thompson and wife #2.

Analysis of the 914cM of DNA shared by DT and AT, suggests that, in all liklihood, DT, AT, and the other Thompson cousins tested thus far are all descended form Samuel Thompson and the same woman. Although the 914cM shared by DT and AT allows for a slim possibility that half-first cousins, the Shared cM Project indicates that the same linkage provides for a much greater liklihood that DT and AT are full-first cousins.

Further Analysis

The DNA tests of our four individuals ostensibly descended from Samuel Thompson's two wives strongly suggests that Samuel's two wives were either closely related or in fact the same individual. If Samuel's two wives were sisters, then their offspring would be three quarters-siblings to each other

The cM linkage shown is the amount shared with Shaw family member GSM (test subject P). Because the shared DNA in JA's family group falls below a 40cM threshold, Tools such as DNAPainter.com's What Are The Odds tool won't be useful to us in this particular case. Further, the Most Recent Common Ancestor (MRCA) of this Rivron family group does not suggest a connection to our Shaw family — and the MRCA of this family group is realistically too recent for such small DNA matches to connect to our Shaw test subjects through an NPE. CMA also assigns a Genetic Complex to JA based on the Shaw family test subjects that JA and her family group match. In this particular case, JA was assigned to the [Shaw-Jones] genetic complex — which is to say that (referring to the diagram of our Shaw family test subjects) JA and family are either direct descendants of one (or both) of my GGG Grandparents John Shaw and Susannah Jones or share a common ancestor with one or the other of John or Susannah. Because JA and her family don't share significant linkage with any of our Shaw family test subjects, it's extremely doubtful they could be direct descendants of John and Susannah — and since we know that John Shaw was born in Scotland and none of JA's family has any discernable Scottish ethnicity (and their recorded pedigree doesn't suggest any such connection) — it's reasonable to conjecture (at least for the time being) that JA's connection to our Shaws is through Susannah Jones' pedigree.

So, just where do we go from here?

Analytic AlternativesDespite the low centiMorgan linkage of JA's Rivron family group, a number of analytic alternatives present themselves as we attempt to connect JA to our Shaw family:

• Perform a "Reverse CMA"
• Use Shared Match predigrees
• Find a "reciprocal JA"

1. Perform a "Reverse CMA" — my original research methodologyThe CMA process used the DNA matches of our nexus individual (Shaw family group subject A) and the DNA matches of related test subjects (Shaw family group subjects B through P) to identify JA as an individual significantly connected to our Shaw family, most probably through the ancestors of Susannah Jones. CMA does this by evaluating the Most Recent Common Ancestral Couple (MRCAC) shared by subjects B through P with our nexus A. If we were able to download the full set of JA's DNA matches, we could begin a "reverse CMA" by designating JA as our nexus individual, and using the DNA matches of Shaw family test subjects A through P as family members connected to JA through a "mystery MRCAC". Although JA does not match every Shaw family subject A through P, the CMA process would provide us with a subset of JA's DNA matches which also match our Shaws. We could then build up and/or examine the pedigrees of this subset, beginning with those individuals sharing greatest DNA with JA, in order to identify which of JA's grandfather's ancestral lines are common to our subset of Shaws, and hopefully identify a connection with our [Shaw-Jones] family. Unfortunately, although JA's connection to our Shaw line was first identified in late 2021, and we have reached out to JA, we yet to receive a reply from her, so this approach is something of a non-starter for the time being. 2. Use Shared Match pedigrees A survey of the individuals listed as "Shared Matches" between JA and each of the Shaw family subjects might generate a list of candidates whose pedigree might connect one of JA's grandfather's ancestral family lines to our Shaw family. Unfortunately, JA's Shared Matches with each Shaw family test subject included only known members of our Shaw family. AncestryDNA's ProTools Extended Shared Matching provided us with the lower cM matches of JA's son DA and cousin CW, but nothing in the way of further "actionable intelligence" — so our efforts to identify which of JA's grandfather's ancestral lines might connect with our Shaws remained unfulfilled. 3. Find a "reciprocal JA" — file this solution under "never stop testing; never stop looking" Back in 2021, when JA's significant connection to our Shaws was first identified, our roster of Shaw family test subjects only went as far as subject I (individual AS) and, while JA clearly shared DNA with a broad range of our Shaws, there was nothing to suggest that any of our Shaw family test subjects shared anything similar with JA's family — as JA only appeared as a low-cM Shared Match amongst other known Shaw family members. This changed when we were able to obtain the DNA test results of Shaw family subject P (individual GSM) in September of 2024. In addition to a 21cM match with JA, GSM's DNA matches included a 92cM match(!) with individual DC, whose Shared Matches with GSM inluded several heretofore unknown individuals whose pedigrees converged in the ancestral lines of the Bowman family, descended from Christopher Bowman (1788–1871) and his wife Christiana Jones (1787–1871):

From her dates and place of birth (Westminster, London) Christiana Jones would appear to have some significant connection to my GGG Grandmother Susannah Jones (1781–1859), who married in Westminster in 1800.
With the ancestral relationship of these shared matches established, it became easier to attach additional family members to our Bowman family, including JA's family, as her grandfather's mother was a Bowman:

• In the above diagram, horizontal lines of the same color (black, magenta) indicate full-siblings; green and yellow connections are half-siblings.
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• Individuals in the diagram have been color coded as follows:

• Beige individuals share DNA with Shaw family test subject GSM (linkage to GSM is shown), in addition to other Shaw test subjects.
• Green individuals share DNA with Shaw family test subjects, but not with GSM.
• Red individuals are Shaw family test subjects.

Observations Although other relationships are possible — for instance, Susannah and Christiana Jones could be paternal first cousins — at the present moment, I'm inclined to treat them as sisters, particularly because of their geographical proximity. With regard to our Shaw family test subject group, it's interesting to note that even though we'd previously tested GSM's sister, CSM, her DNA test results in no way suggested the sort of connection to the Bowman family group that GSM's results made abundantly clear — so the utility of "never stop testing" cannot be overemphasized. The 92cM match between GSM and DC — with a 4th Cousin 2x removed relationship — places the match in the top 0.3% of reported cases (per the Shared cM Project), suggesting that DC may have a connection to GSM somewhere on her maternal lines, in addition to her paternal connection through the Bowman family. Since DC appears to share an elevated amount of DNA with a cluster of individuals belonging to neither the Bowman nor Shaw families, it's entirely possible this supplementary ancestral connection is through a different Jones sibling. Had we been able to aggregate the In Common With matches of JA and our Shaw family test subjects using a reverse CMA process, we very likely would have obtained a similar grouping of Bowman family members through which we'd connect to our Shaw family group, but that remains something to attempt at a later date. Conclusion and Future Considerations With DNA matches involving a total of 42 documented individuals between the Bowman and Shaw familes, the significance of the relationship between these two family groups appears assured. A further collection of DNA matches, shared by both Bowmans and Shaws but without significant linkage to either group, suggests the existence of one or more as yet unidentified Jones siblings whose descendants may assist in identifying the parents of Susannah and Christiana Jones.

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