Thursday, June 30, 2016

Lazarus and the Good Folks at

The last stop on my coming trip to the United States is at the Conference of the International Association of Jewish Genealogical Societies in Seattle where I'll be giving three presentations.

One of the three is called "'s Lazarus Tool As It Applies to Two Kinds of Endogamy" and this is the official description:
Lazarus is a tool offered by GEDmatch which can create a partial genome of a person, based on autosomal test results of descendants on one hand and non-descendant relatives on the other. This recreated kit can be compared to other kits in order to help determine and clarify relationships. But for endogamous families, this is more complicated, especially when you consider that there are two distinct types of endogamy. This presentation will address the two types of endogamy and the way to best use Lazarus while reducing "contaminated" input inadvertently introduced due to multiple relationships. It will also address the use of Lazarus as a tool for DNA analysis. The presentation – much of which is based on the speaker's recently published book "ENDOGAMY: One Family, One People" – will use examples from the single-surname Pikholz Project.
I have been working on this presentation for some time and as I went into the stretch a week or so ago, I needed to look at the results comparing a number of relatives with the Lazarus kit of my great-grandfather Hersch Pickholtz. I summoned the kit as usual and it came up with my great-grandfather's matches in descending order beginning with Aunt Betty, Uncle Bob, Cousin Herb and my sisters and cousins. That is the standard format.

As I have mentioned here before, I name my GEDmatch kits so they will sort together and near the top, otherwise they would not all make the cutoff of 1500 matches that GEDmatch   permits. The naming system also make it easier to see all our kits together, sorted by family group.

So as usual, I hit the small blue triangle at the top right of the "Name" column to initiate the sort. And I got an error message.

I tried a few unsuccessful workarounds while attempting to attract the attention of the GEDmatch team to address the problem. After a few days, I heard from John Hayward, a name I did not recognize. He said that he did not have the problem I described and realized that it was a function of my very large number of matches. He made some changes so that the system would take my top 6000 matches, delete those with privacy issues and then give me the top 2000 matches by whatever criterion I was using to sort.

(It seems that they had raised the number of matches they show from 1500 to 2000. I am not sure if someone announced this but if so, I missed it. In any case, this increase was sorely needed as the total database has grown significantly in the past couple of years.)

This solved my problem and I got my 2000 matches sorted in alphabetical order on the "Name." column. With those parameters, my great-grandfather Hersch Pikholz had matches with eight of the fifteen Pikholz descendants from Rozdol, forty-four of the fifty-two Pikholz descendants from Skalat and one of the three Pikholz descendants whose affiliation is unclear. And another eleven matches with non-Pikholz parts of the family.

John then suggested that he could increase the match limit from 6000 to 50,000, allowing lesser matches to be included in the "Name" sort - still with the limit of 2000. I suggested that we try it to see what difference it would make and after a few minutes the new sort was ready.

My great-grandfather now matches eleven Rozdolers and fifty Skalaters. That served my purposes better, as it increased the number of my great-grandfather's matches by over 15%.

Thank you, John Hayward and the (volunteer!) GEDmatch team. You have been good to us.

So now I can get back to completing my Lazarus presentation for Seattle and preparing to leave for the US in less than two weeks. Wasn't I just there?

Housekeeping notes
14 July 2016, 7:00 – Congregation B’nai Shalom, 701 W. Aptakisic, Buffalo Grove Illinois, RSVP

24 July 2016, 1:30 – JGS of Maryland Hadassah, 3723 Old Court Rd., Suite 205, Baltimore
Beyond A Reasonable Doubt: What We Know vs. What We Can Prove

25 July 2016, 7:00 – Fairfax Genealogical Society, JCC of Northern Virginia, 8900 Little River Turnpike, Fairfax VA

28 July 2016, 7:00 – Robinson-Spangler Carolina Room (Charlotte Mecklenburg Library) and the Levine-Sklut Judaic Library, Jewish Community Center in Shalom Park, 5007 Providence Road, Charlotte, NC

31 July 2016, 1:30 – Triangle Jewish Genealogical Society, 6905 Fayetteville Road, Suite 204, Durham NC (across the street from SouthPoint Mall)

4 August 2016, 12:00 – The Public Library of Cincinnati and Hamilton County, 800 Vine Street, Cincinnati
(Genealogy and Local History Department, Third Floor)

7-9 August 2016, TBA – 36th IAJGS International Conference on Jewish Genealogy, Sheraton Seattle Hotel:
Sunday 9:00 AM  Lessons in Jewish DNA – One Man’s Successes and What He Learned On the Journey, Grand Ballroom D

Sunday 4:30 PM’s Lazarus Tool As It Applies to Two Kinds of Endogamy, Room Willow A

Tuesday 3:00 PM  Beyond a Doubt: What We Know vs. What We Can Prove, Grand Ballroom C

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