Thursday, March 12, 2015

Lazerus Kits For My Mother

The kits I was able to produce for my father using the Lazerus tool at GEDmatch have been easy. I have four descendants (one more is stuck in the lab in Houston) for Group 1 and various combinations of Group 2, which allow me to weed out most of the endogamous relationships. But no matter how I have done it, I get kits with at least 3400 cM.

Considering that GEDmatch defines success by "Batch processing will be performed if resulting kit achieves required threshold of 1500 cM," my father's kits are excellent.

My mother is a different matter. Mother has the same four descendants for Group 1, but candidates for her Group 2 are in short supply. My father has a living sister and brother - my mother has none. I have two first cousins on my mother's side - a son of my uncle and a daughter of my aunt - who qualify, plus two second cousins on either side, though one of those four, Beth, is not yet on GEDmatch.

So for now, I went with what I had. All the tests are FTDNA's Family Finder.

Everyone in the bottom row has done a Family Finder test.

I decided to create three Lazerus kits for my other - one with the five cousins, one with just my two first cousins and one with Kay alone.

The kit with four of Mother's children in Group 1 and five of my cousins in Group 2 gave my mother 3137.4 cM.

But that is problematic. All of my mother's grandparents are from the same general area. Israel David is from Borisov, in what is now Belarus. Etta Bryna is likely from Borisov or nearby. So is Aunt Mary's husband.

Chana Kugel is from Pleschenitsy, now in Belarus, and Hirsch was born in Dolginov, just across the border in Lithuania. Uncle Hymen's wife is from Schedrin, a hundred miles from Borisov. So there is a high probability of a significant amount of overlapping ancestry.

So I cut back to my first cousins, eliminating any endogamy from my second cousins' other grandparents. The size of my mother's kit decreased by twelve percent, to 2766.4 cM. I thought it would shrink more. Some of that decrease is real and some is because endogamy had created a larger kit to begin with.

However, I was able to eliminate the endogamy entirely. Kay's father has no Jewish DNA, so if I used her alone in Group 2, there would be no endogamy at all. The results here surprised me even more. This Lazerus kit had 2188.8 cM. That's nearly eighty percent of the kit that was made from Kay and Leonard together in group 2.

Finally, for sport, I did a fourth kit using Leonard alone in group 2. That kit had 1527.6 cM. Kay's match with us is 43% greater than Leonard's, even with any endogamous effect that Leonard's mother might have.

Note that all these kits, including those with one person in Group 2, are above the threshold that GEDmatch sets for batch processing.

Blaine Bettinger who blogs at The Genetic Genealogist, is doing a study on the amount of shared DNA in known relationships. If you haven't participated, you should. I imagine the findings above will interest him.

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