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.

A Very Deep Connection or Just A False Segment

Every few months, I look at the recent FTDNA matches of my 100+ family kits. I save all those which the company calls "third cousin to fifth cousin" or closer, put them in separate spreadsheets for each of my families and sort by match names. Then I go through them painstakingly looking for matches which look worth following up, based on the longest matching segments. Most of my fully Jewish kits have 2-300 such matches.

Then I write to the matches and ask them to give me their GEDmatch kit numbers so I can run the match against each family, using the indispensable Multiple Kit Analysis on Tier1.

In this round, covering the previous five months, I wrote to eighty-nine people and after two weeks thirty-one have responded. I consider that a good rate of reply, perhaps helped by the fact that people are stuck at home with nothing to do. Some of those give me other family kits to check as well.

It is rare when one of these turns out to be an actual, identifiable relative - either of mine or of some of my cousins - but I find the exercise useful in giving some direction. (I plan to write about a new actual relative later this week.) I also get an occasional new match on one of my special segments, such as the right end of chromosome 21.

Then there is Helen's match.

Helen has a run of the mill match on chromosome 19 with six Pikholz descendants which is too small to be useful, probably going back well before 1800. Not only is it small, but it only includes a few of the twenty-odd family members who might match that segment.

On chromosome 10, Helen has an unusual match with both my half second cousin Fred, my fifth cousin Cyndi (over 15 cM) and Cyndi's brother. Fred's only Jewish grandparent is my paternal grandmother's half sister, so matches with Fred do not have the endogamy which so complicates our Jewish research. This should be my great-great-grandmother's Zelinka from Trencin County Slovakia, where they lived since at least as far back as the mid-1700s.

On the other hand, we have tests from descendants of my grandmother and her full brother and sister and they do not share this segment. So perhaps this segment is from Fred's grandmother's other side, who lived in Budapest.

None of this rings any bells for Helen.

Then I ran Helen's kit against my mother's side and found these two segments on chromosome 7. The one on the left is about 12 cM and the one on the right is 18 cM. The matches are with one of my first cousins and his nephew. Since there are no matches with the rest of my family, this clearly appeared to be on my cousin's mother's side, where the known surnames are Kalson (or Keilson), Sadofsky and Brinn, all from Lithuania.

Then I took a more comprehensive look. The segment on the right includes five near-identical matches of nearly 8 cM with my brother, two of my sisters, my paternal second cousin Susan and Fred. And everyone triangulated with everyone else.

There seemed only three possibilities. Perhaps my maternal cousins' Lithuanian ancestors and my own Slovakian Zelinkas or Rosenzweigs had a common ancestor who left us some common DNA. Perhaps the set of seven small matches were a false segment that somehow carried through to five descendants of my great-grandparents. Or perhaps only Fred and Susan's segments are false and this segment is on my mother's side, shared with her brother's son and grandson.

That third possibility seems wrong to me. But I am not enamored of either of the others.

But Helen has one other segment that may shed some light. On chromosome 10, Helen has a segment of 15 cM with Fred and 10 cM with my cousin's nephew. And they triangulate.

It is hard to call this one false. So there really appears to be a long ago common ancestor of my Slovakians and my cousin's mother's Lithuanians.

I think. Helen, of course, has no idea.