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  #1  
Old 29th December 2017, 06:38 AM
Ana E Ana E is offline
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Discovering a 10cM segment shared only with AJ

I would appreciate some feedback to interpret by ancestry test. In short: I’m largely pure Spanish but it picks some British ethnicity and possibly some jewish. These are low level results and I haven’t been exposed to these tests until now.

—— BACKGROUND TO MY ROOTS:

As far as we know my paternal side is all from the south of Spain, probably with some Portugal mixed in. My maternal side is also as far as we know 100% Spanish, so I was curious to see if anyone could score 100% Iberian.

There is a possibility of some Sephardic roots to my mother maternal line because of their surname and origin (Pardo family, from Segovia in Spain, and area notorious for its Jewish roots). That said, it is also very likely that for the last 500 years only conversos remained in the area, and nowadays Pardo is common enough to have 500 years of non-jewish tradition and blood. This would be my maternal great-grandmother. My mother has no recollection of mentioning any jewish roots (last century Spain is quite anti-semitic) and her mother was a single child with no cousins and hasn’t been around for the last 30 years.

—— MY TEST RESULTS:

I took the test in Ancestry.com. Ancestry results:

- 54% Iberian peninsula
- 23% Europe South
- 11% Great Britain
- 4% Europe West
- 3% European Jewish (0-8%)
- 2% Ireland/Scotland/Wales
- 2% Africa North
(I think it underestimates my iberian blood, and there might indeed be some British great-grandpa/ma that we don’t know of)

MyOrigins results at FTDNA:

- 96% European (86% Iberia, 5% Southeast Europe and 5% British Islands)
- 5% Jewish Diaspora (5% Sephardic)
(I think 85% is indeed my most likely iberian background, and keeps showing some part-British great-grandpa/ma that we don’t know of!)

GedMatch Jtest 4-ancestors Oracle (kit A454664)

Admix Results (sorted):
# Population Percent
1 ATLANTIC 29.40
2 WEST_MED 23.08
3 NORTH-CENTRAL_EURO 15.93
4 EAST_MED 9.21
5 ASHKENAZI 6.89
6 SOUTH_BALTIC 4.85
7 MIDDLE_EASTERN 4.36
8 EAST_EURO 4.30
9 WEST_ASIAN 1.08

Using 4 populations approximation:
1 ES + ES + French_Basque + PT @ 3.436879
2 ES + ES + ES + French_Basque @ 3.480321
3 ES + French_Basque + PT + PT @ 3.646971
(Part of my Spanish is Basque, 3 generations back, and we know there is some portuguese on us too so I would think this 4 population estimates is very good)

Eurogenes K-13 has me as one part portuguese 3 parts spanish which sounds quite right.


—— QUESTIONS TO THE EXPERTS:

+ Should I take that 5-13% British signal as a real person in my family? I consider the italian signal to be probably part of a regular Spanish background due to historical proximity, but British should not.

+ What would be the Admixture for a true Sephardi? (if I got some I am diluted by at least 4 generations) Should Sephardic jews have any Ashkenazi in them?

In the next post I will tell you a cool research story about a large (10cM) DNA segment that I have where I find about 70 matches.
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  #2  
Old 29th December 2017, 06:42 AM
Ana E Ana E is offline
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Second post on my GedMatch research, uncovering a large (10cM) segment in chromosome 2 shared by about 70 people of which they are all 100% or 50%AJ plus me and one other Spanish woman who seems otherwise not related to me.

Note: I have a PhD in cell biology, have done much DNA sub-cloning and created transgenic mice. I have never done research in genealogy but my background meant I found GedMatch and its capabilities truly fascinating.

—— GEDMATCH RESEARCH (my kit is A454664):

I didn’t know if 6.89 was noise or real (remember if anything I might come from Sephardic, not Ashkenazi roots), so I did what khazaria recommended to look at "People who match one or both of 2 kits” using his kit (T544042) as the second kit, serving as a “bait” to identify potential Ashkenazic (his majority of matches) who might also match me.

We had 9 shared matches, and all match me in the same segment in my chromosome 2 (which khazaria doesn’t have, but they must match him in other areas). The segment goes from roughly 124797336 to 134606441. They match me 10.2 to 11.5 cM so that’s a sizeable segment!

I run them all one by one through the Jtest and they all scored 26-31 Ashkenazi (pure or almost pure AJ).

I used one of my longest matches to do again a "People who match one or both of 2 kits” using this other kit (possibly closest to me than khazaria) and we have 126 matches in common, of which 71 are in that chromosome 2 segment! (7-11.5cM)

I have manually checked each of them in the Jtest and found only 4 of us that are not AJ, majority are 26+ Ashkenazi in the Jtest, a few are half. Of those of us who score less Ashkenazi (score 5-9 Ashkenazi in Jtest) three of us are mixes with Portugal in our 4 populations approximation, so I start getting the feeling that we might come from a shared branch.

Following again the excellent khazaria recommendations, I looked at the predicted ethnicity of that segment in the top 8 of us that have all an A code kit (AncestryDNA), to make it more accurate. The largest prediction for that segment is WEST_MED in all of us, and when I do the “compared section shared” search, that eliminates in black the non-shared ethnicity estimates, it becomes more clear that the ~10cM shared segment among this population of around 70 kits (large majority AJ) is mainly WEST-MED with some EAST-MED (Levantine?), ASHKENAZI and MIDDLE-EASTERN. That seems compatible with an ancestor that might have been Jew mixed with Spanish.

I am thinking that this person could have been a Sephardic jew, with a bit of Ashkenazi in him/her, that left a few of us in Spain/Portugal and that married into Ashkenazi outside of Spain, so that whatever many generations after most survivors are now pure AJ.

It is fascinating that one could get this level of resolution.

I have by now identified other smaller areas where I have multiple matches, although never in that scale of 70 matches. I have a segment in Chromosome 11 (from 3847429 to 8272072, 7-8.2cM) where I have 7 matches and they happen to also be also all pure AJ (26 and above in the Jtest). The ethnicity of this shared segment is largely EAST-MED, with some MIDDLE-EASTERN and a bit of Ashkenazi and west_med, so I’m thinking this is not a Sephardic origen segment like the one in chromosome 2 appeared to be. These are also different people.

There are other parts in my DNA where I have other small clusters of 3-8 people, and there are have low Ashkenazi in the Jtest and the fragments are largely south_baltic and atlantic in the predicted ethnicity function, so those where inherited from another branch.

I have upgraded to Tier1, looked at all people who shared those segments, and it is now clear that I am not biasing the selection by using the "People who match one or both of 2 kits” function adding khazaria or one of my AJ matches as a “bait”, those two areas of my DNA in chromosome 2 and 11 are clear matches with people that today is largely pure AJ with some being 50%. And then there is me ;-)

I have ordered two more tests and will sequence my parents. I have also ordered a mitochondrial test for me.

—— QUESTIONS TO THE EXPERTS:

+ Do these segments (mainly the 10cM+ one in chromosome 2 with ~70 matches) indicate a shared ancestors? the matches triangulate with each other too.

+ Have you often come across this type of segments that seems to be so unique to a particular cluster of people?

+ Is there an estimate of how many generations back you have to go to only have one fragment of that 10-11cM length in common? Gedmatch gives me a 5 generation separation from my chromosome 2 matches but I feel it must be further back.

+ Is there a way to know if the ancestor was jew from outside of Spain that married in (or his brother/sister) or a Sephardi that married outside of Spain leading to the mini-iberian cluster of low Ashkenazi people like me in Iberia and leaving many Aj outside?

+ How can you tell Sephardi blood in GedMatch/Jtest?

Thanks for reading!
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  #3  
Old 29th December 2017, 07:10 AM
khazaria khazaria is offline
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Sephardic DNA has been located among some other people in modern Spain and Portugal so this does not surprise me. It is always a good sign when there are matches between Ashkenazic Jews and populations that were isolated from Ashkenazim until recently including Spain, Portugal (both the mainland and the Azores), Mexico, New Mexico, Puerto Rico, the Dominican Republic, and Cuba.

Yes, there is a shared Sephardic ancestor from Spain from the 1400s or 1500s when triangulation was successful, as you report happened in your case, since your ancestry is Spanish.

Some Sephardic Jews of the Mediterranean region have small amounts of genuine Ashkenazic ancestry. Some Sephardic families even have generic surnames like Eskenazi or (rarer) specific German-origin or Slavic-origin Ashkenazic surnames. As an example, kingjohn's mother from Bulgaria whose Jewish half is Sephardic matches my father and I on two segments that phase but we think the common ancestors were Ashkenazim because there are no matches to the segments from the Hispanic world nor from other Sephardic communities. Also, she scores some points of "Ashkenazi" in some of the ethnicity calculators, though that alone cannot be used as confirmation.
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  #4  
Old 29th December 2017, 07:24 AM
Ana E Ana E is offline
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That's very interesting, thank you khazaria. And thank you also for all the advice on how to use GedMatch to identify chromosome sections and check their ancestry that you have left in the forum. I found that extremely useful when doing my research.
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  #5  
Old 29th December 2017, 06:53 PM
josh w. josh w. is offline
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Quote:
Originally Posted by Ana E View Post
That's very interesting, thank you khazaria. And thank you also for all the advice on how to use GedMatch to identify chromosome sections and check their ancestry that you have left in the forum. I found that extremely useful when doing my research.
,

As Khazaria has noted,
there has been migration from Iberia to eastern Europe. (We both share that history) Some Ashkenazi lines may even be Sephardic in origin. It has proven difficult to separate Sephardic and Ashkenazi autosomal lines.
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  #6  
Old 29th December 2017, 09:50 PM
jimbirk jimbirk is offline
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I looked at your kit on GEDmatch and offer this opinion.

Your matches on Chromosome 2 are Jewish and look like a pileup (Identical By Population - IBP). This means the common ancestor is most likely 10 to 20 generations in the past.

Your matches on Chromosome 22 look to be mainly British/Irish and look like another pileup for most of the matches.

With your top match sharing only 20 cM and a MRCA of 4.7 I don't see any easy way to determine how you are related to anyone on your list.

As time passes and more people test you should get closer matches.
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  #7  
Old 30th December 2017, 09:04 AM
josh w. josh w. is offline
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Quote:
Originally Posted by jimbirk View Post
I looked at your kit on GEDmatch and offer this opinion.

Your matches on Chromosome 2 are Jewish and look like a pileup (Identical By Population - IBP). This means the common ancestor is most likely 10 to 20 generations in the past.

Your matches on Chromosome 22 look to be mainly British/Irish and look like another pileup for most of the matches.

With your top match sharing only 20 cM and a MRCA of 4.7 I don't see any easy way to determine how you are related to anyone on your list.

As time passes and more people test you should get closer matches.
Great information. I actually experienced a similar situation. I always thought I was close to 100% Ashkenazi. I was notified that I had FF 5+ Hispanic cousins--as well as 5+ cousins from the Azores. It is likely that they were Sephardic conversos. They should have been 10th FF cousins. Some were aware of Sephardic ancestry, but my matches from Nuevo Leon, Mexico had no interest in discussing Jewish ancestors. From other sources I discovered that the Mexican matches were from Cadiz and the Duoro River.
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