Is this really reaching?

+4 votes
212 views
Here's a quick DNA question. I have a DNA match who is a Third cousin twice removed. We share 7cMs across one segment.  Would that be enough to DNA confirm a relationship with our MCRAs? Here they are:

https://www.wikitree.com/wiki/Fisher-12229 and https://www.wikitree.com/wiki/Frothingham-50

My ancestor is their daughter, Evaline and hers is their daughter, Emma. You would think it'd be greater than third cousins but the paper trail and building the tree down to the match doesn't lie.

So, is it even feasible to even DNA confirm that far back? With my mom, the match is about the same position.

I also want to DNA confirm https://www.wikitree.com/wiki/Felker-207

The thing is my match is from a different wife than my ancestor. My match is from Gertrude Frances Stevens. His line is from Mary Pierce. How would I DNA confirm that? We are 191 cMs across 8 segments.
in Genealogy Help by Chris Ferraiolo G2G6 Pilot (449k points)
edited by Chris Ferraiolo

3 Answers

+5 votes
Just on the basis of that one segment, that's not enough under WikiTree's standards or genetic genealogy best practices in general.

It's possible for a 7cM segment to be IBP (identical by population) in some cases, especially if there are relatively few SNPs.

The bigger issue is that this segment could easily have come from some other unknown common ancestor.

It is possible to confirm that far back, but hard to do so definitively. You would need more matches with shared segments to triangulate the segment.

Just having that 7 cM segment is evidence of a relationship but is not by itself good confirmation of a specific shared ancestor. Also, the extrinsic evidence of the pedigrees connecting to the shared ancestor has to be evaluated.

Given you are on AncestryDNA, check shared matches and see if you can find more who have these ancestors in their trees. If these ancestors end up in a DNA Circle at AncestryDNA that is decent evidence of common descent. But you can't do direct triangulation on AncestryDNA and there is no chromosome map there. You would need to get your shared matches to transfer their DNA to GEDmatch (or FTDNA, or a similar tool).
by Nathan Kennedy G2G6 Mach 2 (27.1k points)
edited by Nathan Kennedy
I didn't think so, Nate. Talk about a shot in the dark. I also edited to include another question. This match is 191 across 8. More solid than a seven!!! The thing is his line goes through a different wife than the one my ancestor does.

How would I dna confirm that?
Only 191 SNPs? That's would be a real paucity of SNPs across an 8 cM segment. Usually you want to see at least 500.

Google "DNA triangulation" or start here: https://www.wikitree.com/wiki/Help:DNA_Confirmation

It's a large subject covered exhaustively elsewhere and I cannot repeat it all here.

---

Addendum: Is the 7 cM segment match really between you and your cousin? It appears your parents are DNA tested. Does your expected parent share that segment, or better yet, a larger segment that includes that 7 cM segment? If you have a match not shared and neither of your parents shares that match, then it is Identical By Chance and that "match" or "segment" is meaningless. If your parent does share it, then you can match on the larger segment or phase your segment which makes for more reliable triangulation. This is again a large, hairy subject. https://dna-explained.com/ has some articles on this topic.
I had an easier time DNA confirming a lot of the first thirty in the tree as seen here: https://www.wikitree.com/genealogy/Ferraiolo-Family-Tree-2

Check that out.

The matches I used to DNA confirm everyone there were mostly in the 1st through 4th cousin areas. The third cousin twice removed surprisingly falls within those gens. I was surprised to see such a small cM count.

It is what it is. I'm not going to bother. I am going to look for closer and the match that I'd like to confirm now is a lot sturdier, I guess? The other match was on shaky ground. However this one is from one common ancestor and then back to two common ancestors: https://www.wikitree.com/wiki/Felker-208 and https://www.wikitree.com/wiki/Fellows-1015

I would ordinarily check to see if their son, Wilfred, had more children with Gertrude along with Austin. He most likely didn't. Austin got a lot of half siblings in the form of the Senters and Wilfred had kids with Ann Pierce.

So, let's move onto that one. I'll poke around and send messages to people. We'll see how that goes.

Thanks for your help. The only circles I see so far are for part of my Italian side and the Quebecois side.

Re: The Addendum.

The match is 7.4 cMs across 1 segment with me.

With my mom, she is 38.1 cMs across 3 segments....which is a LOT better don't you think? I've DNA confirmed people with less. Not much less mind you.

Another match in the same family has 43.6 centimorgans shared across 3 DNA segments shared with my mom. Confidence: High.

The Felker who I'd like to DNA confirm is 310.4 centimorgans shared across 12 DNA segments with my mom. Range: 2nd to third cousins. Confidence: Extremely High.

This is a little difficult to read, guys. First the one guy is complaining about the paltry 191 SNPs, when it said 191cMs, and now we've got "38.1 across 3 cMs" when I suppose you probably meant "38.1cM across 3 segments". Sheesh! A little attention to terminology and units, please!
This is what happens when you type really fast, Frank. Editing.
Fixed.

A little proofreading goes a long way, folks. Nobody's got a stop watch on you. Don't you hate it how you end up with different font sizes intermixed when you do a little editing? Sometimes we get what we pay for here, I guess. smiley

From personal experience, though, I can tell you that the "Cousins" category and "Confidence level" don't tell you anything that the cM count doesn't. The number of segments doesn't really mean much either. They average about 15cM per segment, from what I've seen & to triangulate you'll only be using one.

Thanks, BTW!
No problem.

Yes. Proofreading does go a long way. Sorry about the font. I was copy/pasting. That changes the formatting a wee bit. Whatever. At least it isn't in Comic Sans?

Thanks for the tip. In my case a fair few of the cousins category has been pretty spot on. A first cousin on both my parents' sides came up as 1st cousins once removed and they are in fact first cousins once removed. Same with second cousins, third and fourth.

It's these two I am having an issue with since the common ancestor has a bit of a split since we have the same guy (Wilfred Felker) as the father but diff mother. It diverged from there.

The other line is a little more complicated. I did the lines down from the matches. J.R. matches more with my mom than her sister. Her sister is the low cM one. There's more cMs with JR and my mom than with my mom and KL
Frank, it did not say 191 cM when I answered. The question was rewritten afterward. I have nothing further to add.
Typos happen when you have a cat on your lap. Truth.
+4 votes
I've been trying to make sense of the confirmation process, and am not really an expert, but as I understand it for more distant than a 3rd cousin you need to triangulate, which means you need another match on the same segment within the right range of relations.

To answer your question "Is it even feasible to even confirm that far back?": Yes. I'm kind of hoping to do a triangulation with a couple of my 4th cousins, myself - our common ancestors were born around 1800. No biggie.

I don't really know what the rule is on your last quandry, but I would think that there should be no reason why you can't easily confirm you common ancestor, without confirming the spouse at the same time. In fact, I'd say it's preferable, in a way. Usually you don't know which parent the DNA segment came from, but in this case you do! I think you don't normally mark the common ancestors in triangulation for that reason, but in your case you ought to be able to.

But with 191cM, you don't need to triangulate anyway. If I remember correctly you get to mark the common ancestors, when the matches are close enough relations. If the rules aren't what they should be, I'd recommend using common sense and just marking the one common ancestor even if the rules don't say to.

Speaking of the rules, I guess they're in flux anyway, so I think I'll wait and see what they come up with, myself.
by Frank Stanley G2G6 Mach 6 (66.8k points)
Right. I am talking about the other match now. The 191. I am just wondering what the rules are when the match is from a different wife than your own ancestors are from.

For example:

Wilfred marries Gertrude and has a kid. My ancestor.

The two get divorced.

Wilfred then marries Annie. My match's ancestor.

Would I match up to just that one or would I then go up to Wilfred's parents, Jeremiah and Elizabeth?
Never mind. I think I got it. (As far as the Felkers go.) What should I do about the other lady?
I have the same question, with a similar situation, but with 3 other cousins who were tested and there is paper trail for all of us back to MRCA.  Here's the deal:

My grandmother's brother is grandfather of one second cousin and his first cousin once removed (my second cousin once removed) and our DNA results also support those relationships.  According to WikiTree, that means my great-grandparents (both of them) are MRCA for us.

There is another second cousin, though, whose great-grandfather was a half-brother to my grandmother and her brother mentioned above.  That says to me that the MRCA relative is only my great-grandfather, since he is the one common to this other second cousin, so I only indicated DNA confirmation for him, and not for my great-grandmother.

WikiTree seems to think that it's an error, though, for not having indicated confirmation for both wives of my great-grandfather, which makes no sense to me.
+1 vote

Update: I've managed to DNA confirm: https://www.wikitree.com/wiki/Felker-441 using this:

 Paternal relationship is confirmed with an AncestryDNA test match between [[Ferraiolo-2|Chris Ferraiolo]] and  W.F.,  third to fourth cousins . Predicted relationship reported by AncestryDNA: third cousins based on sharing 190.8 cM across 9 segments; Confidence: Extremely High.

I then DNA confirmed his dad, Wilfred, and from there his parents Jeremiah and Elizabeth.

That just leaves the woman with the 43.6 cMs across 3 segments: Confidence: High. Shared with my mom She is a 3rd cousin twice removed with me. 

With me she is 38 cMs across 3 segments confidence high and 4th to 6th cousin. I think I will have to source like this:
 

Maternal relationship is confirmed with an AncestryDNA test match between (My mom's url here) and her third cousin twice removed, J.R. Their MRCAs are their 3rd great grandparents [[Fisher-12229|John Sargent Fisher]] and [[Frothingham-50|Frances Miranda Frothingham]]. Predicted relationship reported by AncestryDNA: 4th-6th Cousins based on sharing 38 cM across 3 segments; Confidence: High.

Would that work for her?
by Chris Ferraiolo G2G6 Pilot (449k points)

"Would that work for her?"  No.  You say that the relationship is 3C2R.  That is greater than 3rd cousins.

"Paternal relationship is confirmed with an AncestryDNA test match between [[Ferraiolo-2|Chris Ferraiolo]] and  W.F.,  third to fourth cousins ."  What does "third to fourth cousins" mean?  Presumably you know the specific relationship.  Anything beyond a straight 3rd cousin match (i.e. nothing removed) requires triangulation.

Thanks, Kerry.

I was going to link you to this thread since you helped me with the other DNA thread I posted.

I kind of had a sinking feeling this would not work anyway only because the relationship was so far removed. Pardon the pun. Plus the common ancestors were WAAY back. This probably won't work. I'd like it too but it is what it is.

Third to fourth cousin is what Ancestry gave the relationship between my mom and this lady. It's oddly the same when it  came down to me. When I put everything in from her line down to me, that's when things got a little removed.

I had an easier time with the Felker lot.

So, since I can't do triangulation on Ancestry and this lady doesn't have a GEDmatch account, I can't do much. Just need to find someone a bit more closer, I think. Sound good? Sounds great.

Thanks, Kerry!
Sorry to be the bearer of bad news so often.
That was bad news?

Dude, don't worry about it. It was a long shot because of a few factors:

A. How distant the cousin is.

B. The cM count for her and the other matches around her.

It's no big deal.

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