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Not every test, not in every case

Yesterday, The Legal Genealogist wrote with glee of discovering that a grand uncle believed to have been childless may indeed have left a son.1

Finding possible cousins to chase — particularly, as in this case, cousins in a foreign homeland — is always a joy.

And, these days, it’s bound to provoke exactly the kind of comment that blog post drew. From friend and colleague Jill Morelli: “I hear a DNA story in your future!”2

Well… here I get to give my favorite answer… it depends.

Yes, even this certified and certifiable DNA junkie recognizes that this is only part of the story — and in a case like this isn’t even likely to be much more than a footnote to this story.

Because not every genealogical situation needs DNA testing — and not every DNA test can provide an answer to a genealogical research question.

And because verifying a biological relationship is only a small piece.

Take a look at the family tree of these possible new German cousins:

Geissler tree

Hermann and Emma (Graumüller) Geissler were married on 22 June 1879 in Bad Köstritz,3 a little village in what is now the German State of Thüringen. Arno Werner Geissler was their third child and first son, born in 1885.4 My grandfather Hugo Ernst Geissler was their seventh and last child and second son.5

So the new cousin I may have discovered — Fritz Georg Geissler — would have been a first cousin to my father, Hugo Hermann Geissler.

Neither of whom, I suspect, would be available for testing at this point. My father definitely wouldn’t — he died in 1994.6 And Fritz — son of a man killed in action in 19157 — would be no less than 102 years old if alive today.

So we’d likely be looking at the next generation at best: me and my siblings on my side, and Fritz’s children, if any, who’d be our second cousins. Or maybe even their children, who’d be our second cousins once removed.

Now… what would DNA testing tell us? And what would it tell us that we don’t already know — or couldn’t find out — through paper trail research?

Mitochondrial DNA (mtDNA) testing wouldn’t tell us anything in this case. That’s the kind of DNA, remember, that we all have but that is passed down only by a female to her children, and then only by the daughters to the grandchildren, and so on.8 MtDNA, then, only looks at the DNA of our direct maternal line — our mother’s mother’s mother’s line.

Here, the possible cousins wouldn’t share any mtDNA. My mother’s mother’s mother’s line is straight out of the U.S. southland — Texas to Texas to Alabama — and my new second cousins, if I can find them, would have the mtDNA of their German mother’s mother’s mother’s line.

YDNA testing could confirm that we share a direct paternal line — but only if Fritz or a son of Fritz is available to be tested. YDNA, remember, is the kind of DNA that only men have and that’s passed down from father to son to son in a direct male line.9 So it looks only at the DNA of our direct paternal line — our father’s father’s father’s line.

Here, I have the YDNA signature of my father’s line: several of my brothers have tested, including a paternal half-brother, and — whew! — all of them match each other. If a male in Fritz’s line is available, we could verify that we all descend from Hermann.

That’d be nice.

Autosomal DNA testing could be done regardless of the gender of any of Fritz’s descendants that we find. That, remember, is the kind of DNA we all have and all inherit from both parents and that allows us to find cousins with whom to collaborate and share research.10

With a bunch of us who are my father’s children who’ve tested, we could compare to any of Fritz’s descendants, and expect to see somewhere around 230 centiMorgans (cM) of DNA in common with a second cousin and about 120 cM in common with a second cousin once removed.11

That’d be nice, too…

But neither of those is particularly what I’d want.

The fact is, DNA testing in this case of 20th and 21st century cousins can only confirm what the paper trail should show us anyway: that we share a direct paternal line in the case of YDNA testing or that we share recent common ancestors in the case of autosomal testing.

And as a genealogist, as a family historian, as a chaser of personal lore, I want more than that.

Realistically, it’s the paper trail here that I really want here: the documents and records and stories that fill out the full picture of a life and not just verifying a biological relationship.

I fully understand the value and joy of the DNA match.

But it isn’t everything — and in family history, verifying the biology is only a small piece.


  1. Judy G. Russell, “The widow’s legacy,” The Legal Genealogist, posted 16 Dec 2017 ( : accessed 17 Dec 2017).
  2. Jill Morelli, comment to “The widow’s legacy,” posted 16 Dec 2017.
  3. Kirchenbuch Bad Köstritz, Trauregister, Seite 11 Nr. 11 aus 1879 (Church book, Marriage Register, Page 11, no. 11 of 1879), Marriage Record of Hermann Edward Geissler and Emma Louisa Graumüller; digital image of entry in the possession of JG Russell.
  4. Ibid., Taufregister, Seite 41 Nr. 45 aus 1885 (Baptismal Register, Page 41, no. 45 of 1885), Baptismal record for Arno Werner Geissler.
  5. Ibid., Taufregister Seite 69 Nr. 21 aus 1891, Baptismal Record of Hugo Ernst Geissler.
  6. Utah Department of Health, Death Certificate No. 143-94-000152, Hugo Herman Geissler (19 Jan 1994).
  7. See Judy G. Russell, “Death on the Eastern Front,” The Legal Genealogist, posted date ( : accessed 15 Dec 2017).
  8. ISOGG Wiki (, “Mitochondrial DNA tests,” rev. 1 Aug 2017.
  9. Ibid., “Y chromosome DNA tests,” rev. 4 Dec 2016.
  10. See ibid., “Autosomal DNA,” rev. 5 Dec 2017.
  11. See Blaine T. Bettinger, “The Shared cM Project – Version 3.0 (August 2017),” The Genetic Genealogist, posted 26 Aug 2017 ( : accessed 17 Dec 2017).
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