How far back can dna be matched?

Question

I would love to figure out a mystery in our family using dna matching with cousins. I am looking for a match with someone who is a direct descendent of Roger Kelley of the Isles of Shoals, NH. It has been suggested he could be my 6th GGF. I was able to locate one cousin with a gedmatch # whose family connects through marriage to one of Rogers children, but then she said it is so far back, our dna probably wont show a connection. Is this true?  Is there anything I can do to improve my chances of using dna to solve this?

Answer 1

Hi Colleen, it's true that there's only a small chance that you will share a sizable chunk of DNA with people to prove a 6th great-grandparent.  However, I have numerous triangulated groups for ancestors back several generations, so it certainly is possible.

The only way I can think of to increase your chances of solving this is to get someone a generation further back (i.e. whichever of your parents this line traces through -- or a sibling of that parent) to take the DNA test.  I always work off of my parents' tests since they generally share a larger segment with matches -- and share lots of segments which I didn't get passed down to me.

The other thing that I do is to be on as many of the testing sites as possible in order to maximize my chances of locating a triangulated group.  I've tested my parents with ancestryDNA, FamilyTreeDNA, and 23andMe, and have uploaded their results to MyHeritage and Gedmatch.

Are you using any sort of system or software to help you track these matches?  If not, you might want to use DNAPainter (free to use).  If you come across people that share a DNA segment with you and trace to Roger Kelley, map the segment.  Hopefully you will eventually get others and at some point identify a triangulated group.

Good luck!

Comments

Darlene, you have made my day and I hope you have a wonderful day too! 

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What is DNA triangulation?

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Jerry, DNA triangulation is when three (or more) people all share a common DNA segment.  This is called a triangulated group (TG) and indicates a common ancestor.  Members of a TG can then compare their family trees in order to try and identify a common ancestor or ancestral couple shared by all.

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dad, who (ae. 89) passed away in 2017 before he returned the DNA kit...

Leigh Anne, start looking through your old letters and see if you can find a stamp or a letter envelope that dad licked - you can obtain his DNA from it!

I'm seriously considering this for my grandparents (and greats).

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Darlene, from the responses you've received, it looks like your answer is helpful. I'd love to read it. Unfortunately, my eyes are unable to read the font you used.  I hope you're willing to change it. Thanks.

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Darlene, Thanks for the info :o)  I have compared common ancestors with almost every relative that I have contacted because of DNA findings. IMHO it would just show a common ancestor. It would not give a hint on who my 6  GGrandfather's  parents or siblings would be.

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Jilliane . . . the things we do for love!    Just because it's you!  

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My aging eyes thank you, friend!

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To: SJ Baty

Re: Stamp dad licked for his DNA.

If this works you've made my millennium. Do you have a testing service you recommend for this type of DNA collection? I have lots and lots of letters that I'm certain he licked :-)

Leigh Anne

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https://www.theatlantic.com/science/archive/2019/03/dna-tests-for-envelopes-have-a-price/583636/

Answer 2

There isn't an exact limit for how far back autosomal DNA will match in measurable quantities. However, beyond 4-5 generations back, matches tend to be small and inconsistent. As far back as a 6GG (8 generations), it's definitely possible to have a match, but not very likely. I would agree with the assessment that DNA probably won't show a connection.

Other than having more relatives (and from prior generations) tested, there's not much you can do. Of course, if this ancestor is on a direct maternal or paternal line, Y-DNA or Mitochondrial DNA testing could be useful.

Comments

Thank you for the quick reply, John, and the insight is much appreciated. Is Mitochondrial DNA from my mother and is this a different test from the typical Ancestry.com or 23andme test? Should I ask my mother to take a specific test other than one of those?

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Hi Colleen, to answer your question about mtDNA, this is what we all inherit from our mothers.  Both sons and daughters inherit their mother's mtDNA, but only daughters pass the mtDNA down to their children.  AncestryDNA only tests your autosomal DNA, while 23andMe tests both your autosomal and your mtDNA (and Y-DNA for males), although those are very basic tests and not as complete as you would get when testing through FamilyTreeDNA (FTDNA).  With FTDNA, you can choose which test you want done, i.e. you can initially test autosomal, then later have the mtDNA tested (and/or Y-DNA at different levels for males).  See my comment above with regard to what I would recommend as to which test.

Answer 3

I was able to confirm my relationship to my 6th Great Grandfather through autosomal (Family Finder) DNA by way of a same-surname cousin:

John is the 6th great grandfather of SJ

1. SJ is the son of [private father]  
2. [Private] is the son of Virgie Ella (Ulmer) Baty [confident] 
3. Virgie is the daughter of Laura Elizabeth (Mullins) Ulmer [confident] 
4. Laura is the daughter of Anderson Richardson Mullins [confident] 
5. Anderson is the son of Thomas Richardson Mullins [confident] 
6. Thomas is the son of Thomas Richardson Mullins [confident] 
7. Thomas is the son of Joseph Mullins [confident] 
8. Joseph is the son of John Mullins [confident] 
This makes John the sixth great grandfather of SJ.

I joined the Mullins surname group at FtDNA and there I was able to see all of the Y-DNA descendants of John Mullins.  I then checked my autosomal DNA and found that I am a match to one of the descendants who shares Y-DNA with John (a direct father - son relationship and who carries the Mullins surname).  

Now, I say "confirmed" not proven.  It confirms (to my mind and to the mind of the project leader) that my Mullins paper trail is confirmed.  But, I don't have a bona fide triangulation to this Mullins cousin.  When I do, I should be able to say that my relationship to John Mullins, born about 1718, is proven to be my 6x great-grandfather.

Y-DNA transfers directly from father to son and aside from occasional mutations, it remains mostly intact allowing the confirmation of relationships to father, paternal grandfather, paternal great-grandfather, and so on.  Finding a cousin match to one of these Y-DNA carriers goes a long way in confirming a connection.

Look at all of your matches and try to a male cousin who carries the Kelley surname and see if you can match to that cousin.