Most of my DNA explorations have centered around my Dad’s Norwegian DNA because so many Norwegians have tested and the populations of those ancestors are only mildly endogamous; so it is easy to find new cousins and fun to work with those results.
My grandfather and me, summer 1955
My mother’s father was a German Jew. The number of DNA matches this gives me, my brother, and my two maternal aunts is astronomical. Frequently I will match someone from Eastern Europe for five or six large segments who cannot share an ancestor with us for the last 200-300 years and is even listed as a “distant cousin.” If they were Norwegian, that amount of shared DNA would make them my 2nd cousin.
This has been so frustrating that I just about stopped working on my Jewish DNA. A fellow Jewish researcher told me to ignore matches who did not have at least one 23cM shared segment!
Today there were dozens of news articles about the European Jewish founder effect suggesting that all Ashkenazim are descended from about 350 people who lived in about 1300 A.D. or so. This, combined with a fair amount of endogamy, would explain the large amount of shared DNA among European Jews.
If this were a financial blog you would assume a different Greenspan than Bennett and in fact they may be related, but since Alan won’t do the DNA test, we may never know. Today at the annual IAJGS conference I spent some time chatting with Bennett in the Exhibition Hall. I asked him if they could implement a triangulation feature where when two people match me on a specific segment I can check if they match each other on that spot. He said yes but gave me no time frame …
Bennett Greenspan and Kitty Cooper
Bennett Greenspan is the founder of Family Tree DNA, one of the big three in personal DNA testing. This came about because a newly retired Bennett wanted to prove that the possible Argentinian relatives he had found were related when there was no paper trail showing this. He had read about Dr. Michael Hammer’s work with DNA and the cohanim Y chromosome marker and wondered why that sort of test could not be used for his case. Dr. Hammer laughed at him and said something like “If you knew how many crazy genealogists have been calling me … someone really ought to start a company.” The rest, as we say, is history.
Tomorrow at 1:45 Elise Freeman is going to speak about “Understanding Your DNA Results in the Context of Ashkenazi Ancestry.” I can’t wait to hear her.
The results came in for my other maternal Aunt so now there are four of us to compare to my double third cousin and still no match on the X! In order to show the comparisons I used my new nifty chromosome segment mapping tool and also added in a bunch of known 5th and 7th cousins to the diagram.
Click on the diagram to go to the full size html page made from the segment mapper. Note that Shipley Munson is my brother.
According to family lore, when their business needed money my great-grandmother Charlotte Langermann Thannhauser, on my German Jewish side, fixed up her sister Lina with her husband’s half brother in order to get Lina’s dowry invested in the family enterprise. Not such an uncommon occurrance. I was able to convince Lina’s great-granddaughter on the straight maternal line to test at 23andme. She is almost doubly my third cousin, sharing DNA from the Thannhauser and Langermann lines but not Engel.
Well I thought I had found a real cousin on the German Jewish side due to a few common surnames but no luck finding the relationship yet. Sadly there is a large match on our X but the common surnames are not on a branch where X could come from. Of course one of the problems in German Jewish genealogy is that all but a few prominent families had no fixed surnames (they used their father’s name) until 1813/14.
Even worse she mainly matches me on segments that are what I call “Ashkenazi Pile Ups” or locations where there are well over 30 people matching me but not my Dad for more than 5cm. By comparison I notice only one such pile up on my 100% Norwegian father’s matches at chromosome 9, at about 80,000. But that will be the topic for another post.
These are the three pile ups my new distant cousin matches:
Chromosome 2: 45 matches for this segment at 23andme
Chromosome 4: 80 matches for this segment at 23andme
some start at 18.1 and some end at 25.0
Chromosome X: about 30 matches for me, 50 for my brother…. hmmm
a few are longer than this
For those of you who are wondering where to find this data on 23andme you can download all the segments that match yours with the name of the donor (most will be anonymous) by going to “ancestry labs” under ‘My Results” and clicking on “Countries of Ancestry.” Scroll down the page to the long blue button where you can download a CSV of all your matches. [updated 27 dec 2013 – n.b. you can get this data and more by using the http://DNAgedcom.com site to do the downloads]
There are a few more pile ups in my and my brother’s matches than these …