Help with another DNA question, please!

+9 votes
370 views

I got a strong match the other day, Both of us descend from a John, born in 1764.  He had 2 sons:  

  1. William ,1802-1882
  2. John, 1798-1844

William and John married sisters.  

  1. William married Esther, 1804-1854
  2. John married Eleanor, 1800-1844

William and Esther's line (hers)

  1. William 1802-1882, her 2x ggf
  2. John , (1842 - 1882), ggf
  3. Benjamin, (1875 - 1931), gf
  4. Herbert (1908 - 1989), father
  5. Cousin

John and Eleanor's line (mine) 

  1. John , (1798 - 1844) 4x ggf
  2. Nicholas, (1840 - 1908), 3x ggf
  3. Rebecca, (1870 - 1920), 2x ggm
  4. Lena,(1897 - 1990), ggm
  5. William,(1928 - 2008), gf
  6. My mom
  7. Me

Does this make us double cousins??  We share a total of 110.78 cM of DNA.  That’s quite a bit for so many generations, right?  Is this just completely bizarre? I'm stumped.  Help!   EDIT - ok, it appears we are 4th cousins 2xr.  But this is just strange, seems like a lot of shared DNA for such a long distance between us.....

*Addition on 5/8/16 - Per GEDmatch guidelines: To qualify as a 'match' in the genealogical time frame, results must have a largest Autosomal segment that has at least 700 SNPs and be at least 7 cM.

Chromosome Centimorgans Shared  Matching SNP
1 2.78 1300
1 2.06 500
1 26.12 5675
2 26.98 7200
2 5.45 1600
2 1.05 500
3 1.83 500
4 1.24 500
4 17.83 3500
6 3.69 563
8 1.58 500
10 2.88 700
10 3.49 700
11 1.5 700
13 1.77 500
13 1.43 500
13 1.94 500
18 7.14 2100

 

in Genealogy Help by Summer Orman G2G6 Mach 8 (86.2k points)
edited by Summer Orman
The family finder DNA says we are 3rd cousins.  Ancestry says 4th cousin 2xr.  Anyone???  Bueller??  Bueller??
Summer, my dad, Herbert Fair Lunn's brother Harold Hunter Lunn, has a son, John Harold, my cousin, who took a DNA test. His wife Phyllis and I will get together online (they live in Clinton TN) and sort it out. She will contact me in the morning as she is not sure hat whether it is Autosomal or Y. If it is Y just think how much that would give us on our Lunns! John and Phyllis have one son and he has one son. This just keeps getting better thanks to you!

I'm thinking of getting an Mt-DNA test. What do you think? This would perhaps solve my brick wall. My great-great grandmother, Susan Sisco, born in 1818, had a child "out of wedlock" at 16 with my great-great grandfather, John S or T Turner who died in 1837 in Arkansas. Phebe was "given" to John's Aunt, Phoebe Ann Turner Sisco. Phebe is listed as a Ward of Phoebe Ann's husband, John Andrew Francisco. Susan remarried later in life and had several more children. There were many many Francisco/Siscos, and it may not ever be solved. An aside, the Franciscos (French Huegonots who fled to the Netherlands) go back to the settlement of Bergen County New Jersey, where my now husband's family lives!

I'd love to get an mtDNA too, but I just can't afford it right now, myself. I'm trying to prove an mtDNA match to my 4x ggm Nancy, as I am a direct female-to-female descendant (Nancy> Catherine> Jessie> Charlsie> my grandmother> My mom> Me) so I know I should match her.  Maybe one of these days I will get around to it!

3 Answers

+4 votes
 
Best answer
Unless you indicate otherwise, I assume that you share 4 Most Recent Common Ancestors.  The two parents of William and John, and the two Parents of Esther and Eleanor. I believe this makes you double cousins.

What was the actual prediction of AncestryDNA, including the range and confidence?  AncestryDNA is good, but I didn't think they were so good as to nail it on the head.
by Ken Sargent G2G6 Mach 5 (57.0k points)
selected by Ray Jones
Her DNA is not on Ancestry, I was simply using the relationship calculator there, after connecting our trees.  I don't think she has a Gedmatch either.
And you are correct, the 2 sets of parents are shared!

A Double Cousin will predict a closer relationship. So, in this case, a 3rd cousin prediction appears to be consistent with the paper trail.

What this tells me is that this match will further support the following relationships...

Hers...

  1. John , (1842 - 1882), ggf
  2. Benjamin, (1875 - 1931), gf
  3. Herbert (1908 - 1989), father
  4. Cousin
Yours...
  1. Nicholas, (1840 - 1908), 3x ggf
  2. Rebecca, (1870 - 1920), 2x ggm
  3. Lena,(1897 - 1990), ggm
  4. William,(1928 - 2008), gf
  5. My mom
  6. Me

What I mean but this is that given the existing paper trail, You inherited those segments from you mother, and she from Willliam, etc.

You don't know if a segment received by Nicholas came from John or Eleanor's line. Your cousin has a similar question.

Cousin Jeanne here. Trying to resolve password issue on GedMatch.Thanks again Summer for all your good work!
You're welcome new cousin!!! And don't worry, I can get the lines all straightened out for you!! You did most of the work on your side, now I just have to build up my side!!!
I have bunches of those double cousins as first there were Frenches who married Clarks and the Clarks who married Evanses.  Starting with Sameul Clark two of his sons married Frenches and each of those couples had 3 children who married Evanses.  All 6 of these Evanses were related via David Evans, Sr. One through his oldest son Abraham and at least one via his youngest son, George Washington Evans, but there were differing numbers of generations as Abraham's son David was essentially the same age as GW Evans' was.  Someone want to work out that in DNA genealogy?  But that's the way it was our on the frontier in the early 19th century.
+3 votes
Hey Summer!

I would watch on this, as it appears that you have dropped your minimum cMs to include DNA segments all the way down to 1 cM.  

For distant cousin matches in particular, you should be very wary of dropping down your minimum cMs, as segments under 7 cM in length (arguably even under 10 cM in length) can be false positives.

You have three substantial segments (26.12 + 26.98 + 17.83) and given that you share these three, I would also be comfortable with treating the 7.14 cM segment as real.  As such, you technically have 4 DNA segments in common with nearly 79 cM in common.

Also, I agree with Ken's previous statement about you sharing 4 recent common ancestors.
by Ray Jones G2G6 Pilot (154k points)
Hi Ken,  

I thank you for being so supportive on your post.  I do have to laugh though, because there is so much discussion on errors or the possibility of Non Paternal events....when in fact, my mother WAS a non-paternal event. She didn't know William was her father until she was 30.  He had known about her but while his wife was alive he couldn't admit he had strayed (though I'm told his wife did know).  After his wife passed, he was able to welcome my mother and our family fully.  I was standing at his bedside when he died.  

So, as you previously stated, this relationship "confirmation" between Jeanne and I, serves 2 purposes:  1) To confirm (yes I say confirm) that my mother was Bill's biological daughter, and 2) I have a new cousin!  We may be quite distant and only share a few DNA segments, but that doesn't mean a thing.  We plan to have a relationship.

Summer
I love Science!

I just have to say, it is quite interesting that on the other cousin I posted about, the system confirmed us as 2nd cousins twice removed (consistent with the paper trail) but with Jeanne, the paper trail overrides the DNA Match.  

  • James and I share over 120 cM but only 103 is counted in the total because the rest comes from smaller segments.
  • Jeanne and I share over 100 cM total, but only the segments totalling over  84.5 are counted.  
  • there is virtually NO difference in the MRCA estimation, the only difference is James and I have larger segments in common, whereas Jeanne and I have larger segments overall, but more small ones in common.  Yet, our relationship isn't recognized, even with the paper trail as proof.

Interesting.

  Total cM shared largest cM shared generations to MRCA
Me-James 103.5 26.2 3.6
Me-Jeanne 84.5 27.5 3.7

 

The Family Finder system only predicts or estimates the relationship based on the number and size of the shared auDNA segments.  Testers can tell the system what their genealogical relationship is with their matches and then their relative can "confirm" that relationship. Family Finder then states the known relationship.

Summer, You may find this interesting...

The ability to confirm with DNA is all or nothing.  

Parent-child relationships can be labeled Confirmed with DNA when there is a sufficient amount of shared autosomal DNA between two relatives who are third cousins and closer. It is necessary to use triangulated groups — three or more matches on the same DNA segment — when the testers are greater than third cousins.

A sufficient amount of auDNA is determined by the total number of cMs of several segments normally shared specific relatives. See Mathematical Average for auDNA Sharing andAre There Any Absolutes in Genetic Genealogy?" see help.

You only care about the amount of shared autosomal DNA between two relatives who are third cousins or closer.  You and Jeanne are not third cousins or closer. The guidelines for you and Jeanne are...

"If all the test-takers have uploaded to GEDmatch, use their Triangulation utility or One-to-Many utility (for you and each segment sharing cousin). Find segments measuring 7 cM or more that you share (i.e. overlap) with two or more distant cousins.

Those who all match each other on the same segment form a triangulated group (TG). Using WikiTree's Relationship Finder find the shared ancestral couple for that TG." see help

There are a few interesting things to point out.  The requirements only care about triangulated groups which 3 distant cousins share a single 7cM or greater segment. You don't need to predict the relationship between you and Jeanne.

1. This means that you only have to find one additional distant cousin who shares a single 7cM triangulated segment, to mark all the profiles up to and including the 2 shared ancestral couple.  This is ok when you don't have a paper trail and are looking for clues as to how you are related, but it certainly falls short of proving an existing relationship.

2. You may be a 3rd cousin 1x removed but these rules allow for you to mark all profiles, even if the prediction is distant, based on a single 7cM triangulated.

3. There is no requirement that the additional match needs to be more distant, which means that you are proving pretty much nothing.

4. The x chromosome is obviously wrong, but even if it were corrected. You could Confirm with DNA any match, including a 3rd cousin 1x removed, with a 1cM match on the X Chromosome, even if the prediction is NO RELATION. 

 

"4. The x chromosome is obviously wrong, but even if it were corrected. You could Confirm with DNA any match, including a 3rd cousin 1x removed, with a 1cM match on the X Chromosome, even if the prediction is NO RELATION."

You can go less than 7 cM on the X only when both matches are male.
 

"3. There is no requirement that the additional match needs to be more distant, which means that you are proving pretty much nothing."

For triangulated groups the cousins should be distant ones.  If two people are 1st cousins and the third match is a 5th cousin then it is an insufficient triangulated group.  If the guidelines don't say so already then I believe they should be edited to state that those in a TG need to be distantly related.  Thanks for pointing that out.

"The requirements only care about triangulated groups which 3 distant cousins share a single 7cM or greater segment. You don't need to predict the relationship between you and Jeanne."

The triangulated groups are used to confirm the genealogical relationship in WikiTree. 

Peter, your statement "The Family Finder system only predicts or estimates the relationship based on the number and size of the shared auDNA segments." is incorrect. 

In March of 2013, see blog

the latest version of the autosomal DNA reference data set being used - for the past two months in order to refine their matching algorithms and provide better matches to their customers.  Many customers saw the following message from Family Tree DNA on their homepage this month:

You may notice that some of the matches you had previously are no longer listed. In almost every case, those matches are in the distant and speculative range. Some may be legitimately related, but many were likely “noise”—small coincidental matching segments that create the illusion of matching. The more distant the relationship, the less likely a match can be predicted with confidence. We are aware that you may have spent a significant amount of time researching those matches, but Family Finder was specifically designed to find matches within the past 5-6 generations.


As the field continues to advance, we're obligated to continually apply the latest scientific advances not only to current and future tests, but to those that have already been performed. Sometimes this will involve changes to your results. Because this particular field is still evolving, it is likely that future adjustments will be made to refine your results.

Gedmatch.  see FAQ

Autosomal Comparisons 

Q. Why does the GEDmatch.Com Autosomal comparison give slightly different results than I get from my testing company? 

A. FTDNA uses proprietary 'sets' and 'cM' tables when generating their comparison results. FTDNA's method results in segment endpoints tied to the endpoints of their 'set' data. The GEDmatch.Com algorithm is not dependent on 'sets', and will generate segment endpoints immediately adjacent to points where individual alleles don't match. Genetic Distances (cM) on GEDmatch.Com are calculated based on charts produced by the Computational Genetics group at Rutgers University. 

23andMe and other testing companies also use their own comparison algorithms, and Genetic Distance charts. So, results are bound to differ than what you see here and on other 3rd party sites.

Why is only looking at total cM and then comparing to a generic chart, better?

Hello Ken,

Are saying FTDNA does not use segment size and the number of segments to estimate the relationship?  Or do you believe my statement is incorrect because of my use of the word "only"?  Or something else?  

Thanks.
+2 votes
Hi Summer, I agree with Ray as far as the three substantial segments.  The 7.14 cM on chromosome 18 is very possibly IBD, though. The rest are most likely IBS (identical by state).

You can't be sure of the common ancestor that you're getting this shared DNA from until you have a triangulated group, whereas someone else that descends from John (born c 1764) and his wife matches both you and your cousin on one (or more) of your large shared segments, i.e.the three large segments on chromosomes 1, 2 and 4.

My mom shares 73.7 cM with one cousin, and 126.7 cM with another cousin; they all three share common 2x great-grandparents.  Another cousin shares 98.7 cM with my mom, and they share common 3rd great-grandparents.  So you can see that the amount can be high even with 3rd ggps (great-grandparents).

I'd say the bottom line is that you need to both get on Gedmatch and find/wait for triangulated groups to analyze and try to determine your MRCAs.
by Darlene Athey-Hill G2G6 Pilot (435k points)
I'll still trying to reload raw data onto GedMatch. Stay Tuned!

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