Is a DNA match to a pre-1700s ancestor considered a reliable source?

+2 votes
in Genealogy Help by Genny Edge G2G Crew (500 points)
Assuming you are using atDNA matching and assuming you are not matching the actual ancestor, the answer would likely be a no. In rare circumstances the shared DNA segments of your candidate ancestor could have propagated to present-day descendants, however.  In that case, you'd need a couple of other matches with documented trees showing same common ancestor and all sharing the same chromosomal position of the matched segment.

Typically when there is a pre-1700's match, there is an unknown shared ancestor who lived after that time.
thank you for replying.

I'm sorry, I don't know what a "atDNA" match is.  

these ancestors I'm trying to enter into profiles on my tree are a ThruLine based on my AncestryDNA test.  I have lines that go to the pre-1700s through a direct line from that test at Ancestry which shows every person in the line is listed as a DNA match at Ancestry with the cMs and segments given.
atDNA (or "auDNA") is shorthand for autosomal DNA test.

To be considered reliable, you'd need to know if your matches are sharing the same chromosome segment and position. doesn't provide any chromosomal information unfortunately, rather it only provides segment lengths and counts so you can't know if a particular segment was mutually inherited by your matches (and thus much more likely to be attributed to the same ancestor).

edit to add: As you may already know, Thrulines is a double-edged sword. It can find potential ancestors, but if your matches have incorrect ancestors in their trees, then Thrulines has no problem whatsoever suggesting those incorrect ancestors as if they were also your ancestors.
thank you.  since I replied by email, I won't repeat all that, except to say I appreciate your help and I'm once again "on my way."

2 Answers

+4 votes

A Thruline DNA match to a 1700s ancestor at would not be considered a "Reliable Source", as that term is used for pre-1700 profiles at Wikitree.

Wikitree has much stricter guidelines than or other sites for what it considers "DNA confirmation". See for what Wikitree requires for a DNA confirmation.

I see that you have marked quite a few of the ancestors on your family tree as "DNA confirmed", but the required documentation (as shown on that Help page) appears not to have been put in the profiles. You may want to review what is actually required for DNA confirmation at Wikitree and revisit your marking of "DNA confirmed" on your ancestors' profiles. Once again, a Thruline match on is not enough.

by Anonymous Geschwind G2G6 Mach 8 (81.9k points)
thanks C-H.  I'm proceeding to correct the error of my ways.  I like that WT is so exacting, makes me feel more confident in the DNA matching with the stricter guidelines and the emphasis on "how."  it makes sense, it's more logical
+4 votes
Hi Genny, I had my DNA done at Ancestry and I found a few mistakes in the thrulines. If someone has listed a wrong name in a common ancestor shared by you, that name will appear in your thrulines.
by Ellen Gustafson G2G6 Mach 2 (21.0k points)
thanks, Ellen.  I finally get it, and you're right.  I always thought it was "too good to be true." lol


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