Two GEDmatch Tools Plus More About Testing Siblings

Some weeks ago, a woman named Sherri contacted me via Ancestry.com. Ancestry said we were a very small match - 25 cM across six segments - and Sherri wanted to see if we could follow it up. She was already on GEDmatch, so I had a look.

GEDmatch showed a slightly larger match - nearly 32 cM over four segments, but still not much. Her mother's sister is also on GEDmatch, but she matched me even less, but with only a single segment of 11.8 cM on chromosome 12, where Sherri does not match me even at 3 cM.

I ran Sherri's kit against my families on the GEDmatch Multiple Kit Analysis, using a program called Short Keys to fill in my own kits.

The GEDmatch Tier1 tools

 

Sherri matches a few of my family members on my mother's side on three <12 cM segments, but all of these are matches with various cousins, none with me or my siblings. Sherri's aunt shares one of those three matching segments.

Then there was this, on my father's side. A nice segment of ~25 cM on chromosome 19, with eight of my family, not including me.

We have my brother and three of my sisters, my father's sister, two double second cousins (brothers) and my second cousin Susan. Susan nails this onto my grandmother's side, the one from Slovakia and Hungary. This is geography that Sherri didn't recognize from her own family. It is definitely Sherri's mother's side, as her aunt has this segment as well, although only ~11 cM.

And our match with Sherri is recent enough that a 25 cM segment has been preserved, despite that my Hungarian and Slovakian ancestors were in place at least since the mid-1700s.

(My guess is that Sherri matches my Hungarian great-grandmother rather than my Slovakian great-grandfather due to some other smallish matches she has with one specific cousin on each side, but I am way too conservative to jump to any conclusions here.)

Sherri's match with *G

So I asked Sherri about other family members who have tested and she mentioned a man we shall call *G, whom she has determined is her second cousin once removed. The relevant surname is Feldman from Belarus. Sherri's match with *G includes 37.4 cM on the segment we share on chromosome 19. That match is larger than even what Sherri shares with her aunt (31.4 cM).

My next step was to look at the Segment Search tool on GEDmatch. Like the Multiple Kit Analysis, this is a Tier1 tool, which requires a small payment. (I use GEDmatch enough that I generally pay for Tier1 12-18 months in advance.)

After removing the matches that are (or appear to be) from Sherri's father's side, these are Sherri's other matches on this segment. I removed the emails and kit numbers for privacy and coded the names for the same reason.

The four marked in red match Sherri's family members, but not my family - but they might if they were a bit longer. The seven marked in purple match Sherri's family and mine. The email for *G in the top row is one I recognized. It belongs to Leonid, whom I have mentioned here before. Our great-grandmothers have essentially the same given name and our maternal haplogroups are a perfect match. But that is a different part of our two families.

I wrote to the four people in Group 1 and the seven in Group 2, on the off chance that one of them may know something that can help connect the Belarus Feldmans to my Hungarian (or Slovakian) family. And of course I touched base with Leonid. 

Thus far (after a week) I have heard back from the first two people in Group 1 and the first two in Group 2. None of them has been able to shed much light, but I see that they are more Sherri's Belarus/Lithuania, rather than my Hungary/Slovakia. It looks like my family is the outlier.

Besides telling the story, I am writing about this for two reasons. One is to give a bit more detail on the use of the GEDmatch tools Multiple Kit Analysis and Segment Search. The other is to bang the drum yet again for testing siblings. This inquiry began with a match between Sherri and me. But I do not share the interesting segment on chromosome 19. For that we needed my brother and some of my sisters. Without them, we don't find this.

Furthermore, although we usually place an emphasis on the older generations, had we only had Sherri's aunt and not Sherri herself, this segment would have been only 11 cM and I probably wouldn't have paid it any attention. But clearly Sherri's mother got a larger segment here than did her sister (Sherri's aunt). So once again, testing first and second cousins is of primary importance, but test the siblings too. Why? Who knows! There might be a difference in some segments that matter.

Politzer

Customers of Family Tree DNA are familiar with the match alerts we get from time to time, whether our own kits or the kits of members of our projects.

As I manage over a hundred kits, I am not about to stop what I am doing to look at these every time I receive one and in any case, I want to see how a match fits not just with me  but with other family members including those not close enough to warrant an alert. So nearly two years ago, I decided to look at all the new matches across my family members every few months. Then I write to the ones that look interesting and ask them to upload to GEDmatch to see if these matches are on shared segments.

Usually nothing much comes of it. Even when the DNA points to a very specific portion of my family, the match usually doesn't know any of my surnames or even my geography.

Last week I prepared the matches for the past four months and Sunday I sent out messages to the scores of matches who looked even a little bit promising. So let me tell you about Cynthia, who happens to be the wife of a fellow I actually know.

So I asked her to register for GEDmatch/Genesis and after it batched I looked at her top 20,000 matches using the Tier1 one-to-many search. She matches seventy-eight of my kits and I did some chromosome browsers to see how her matches line up in family groups. As usual I was looking for segments of over 10 centiMorgans with multiple meaningful matches with my families.

On chromosome 3, she matches seven of us - four of my parents' children, one first cousin and two second cousins, all pointing to my maternal grandfather's side. All we have there are the surnames Gordon and Kugel. And it was a small match anyway, so probably from a pre-1800 common ancestor.

Chromosome 5 showed a 12 cM match with a pair of second cousins in the Nachman Pikholz branch of the family. Not much with that either - but if Cynthia had the relevant surnames, it could have been nice.

Chromosome 6 had two segments of minor interest - one with some second and fourth Pikholz cousins of mine and another with one first cousin and three second cousins on my maternal grandmother's Rosenbloom side. Here too, we have no other surnames, but we do know that the
family lived in Borisov (Belarus) for at least half of the 1800s.

Both chromosomes 16 and 20 brought matches with small groups of my third and forth cousins on

the Pikholz side.

Chromosome 22 has seven descendants of my Pikholz great-great-grandparents. Both of these ancestors are Pikholz.

Then there is the X, chromosome 23. The relevant matches look like this.

The four nearly identical matches belong to two of my sisters, my father's brother and my fourth cousin Lydia. They all triangulate, so they are all from a common ancestor.

This cannot be from my grandfather, because Uncle Bob gets no X from his father. So we know it's my grandmother's side. So given Lydia, who is part of my grandmother's paternal grandmother's Zelinka family, how exactly does this fit together and who is the candidate for the common ancestor?

Uncle Bob is a third cousin to Lydia's mother
so we and Lydia are fourth cousins.

Nathan / Nahum Zeinka's fallen gravestone

Our most recent common ancestral couple are Isaak and Sari Zelinka, who were born in the mid-1780s. But Lydia's second-great-grandfather Nathan Zelinka received no X from his father, the source of the match between Lydia and Uncle Bob must be from Sari, Isaak Zeinka's wife.

Nearly two years ago, Uncle Bob's daughter Linda and I were in Slovakia, together with our fifth cousin on the Zelinka side, Cyndi and while in Zilina we met Lydia. In the course of taking down her family information, I asked if she knows anything about our third-great-grandmother Sari. Lydia said that she understood that her surname is Politzer. This made sense to me because many years ago, my grandmother had told me that her father was related somehow to Joseph Pulitzer - he of the prize. - but she had no idea how. I have tentatively recorded Sari as Politzer, pending some kind of actual documentation.

So last year, Lydia gave our third-great-grandmother a name and perhaps a family and now we have an actual bit of her DNA.

(Note, I could have seen this with an analysis of Lydia, having nothing to do with Cynthia, but I didn't - so I can thank Cynthia for that.

Caveat - it is theoretically possible that the segment comes from my grandmother's MOTHER's side and that Lydia has some unknown ancestry in Hungary, but I consider this to be a vanishingly small possibility.

The Matching Segments tool on GEDmatch does not include the x chromosome, but on Genesis it does. They call it "Segment Search" and it is on Tier1. There are about three dozen people who share that match with both Uncle Bob and Lydia and I suppose I should write to them. Maybe something else will turn up.

(What I don't understand is why Uncle Bob and Lydia do not show up on Cynthia's Segment Search. I'll have to speak to GEDmatch about that.)

Housekeeping notes 

Order here.
European Jews have always married mainly within the tribe. Whether our numbers five hundred years ago in Europe were four hundred or four hundred thousand, the pool was limited. As a result, the members of the tribe today are all related to one another, multiple times.  This phenomenon, known as endogamy, makes Jewish genetic genealogy very difficult, often impossible. There is a similar phenomenon in some other population groups.

I was convinced that this brick wall is not as impenetrable as it seems, at least in some circumstances.

I believe that this book demonstrates that I was correct.

When I decided I wanted to write a book, I was not sure if I wanted to write a “How to” book or a “How I did it” book. The decision was dictated by the facts in the field. Different family structures, widely different numbers of living family members, and other similar factors dictated that writing “How to” would be irrelevant for most researchers.

“How I did it” is more likely to be helpful to the research community and more likely to instill the confidence necessary for such a project.

It is my hope that this book will encourage and inspire other researchers of their European Jewish families and other endogamous populations to say “I can do this!”