Sunday, July 19, 2015

Two Very Different Kinds of Endogamy

Two endogamies
The wiki of the International Society of Genetic Genealogy (ISOGG) defines endogamy as
the practice of marrying within the same ethnic, cultural, social, religious or tribal group. In endogamous populations everyone will descend from the same small gene pool. People will be related to each other in a recent genealogical timeframe on multiple ancestral pathways and the same ancestors will, therefore, appear in many different places on their pedigree chart. Endogamy can be the result of a conscious decision or cultural pressure to marry within the selected group but also occurs as a result of geographical isolation (for example, in island communities). 
This pretty much fits with what most of us mean when discussing the difficulties of Jewish genetic genealogy, though some might question the term "recent genealogical timeframe." For serious  research, the issue of endogamy is not a problem of recent genealogical time (the last two-three hundred years) but rather the gene pool of European Jews as it existed twenty generations ago. Each person had 220 ancestors twenty generations ago, which would generally be about five to six hundred years back. This number is something north of one million, which is undoubtedly more than the number of European Jews who lived at that time.

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In this sense, endogamy is not qualitatively different from the pedigree collapse that exists in non-endogamous populations, for they too reach a point when they run out of possible
unique ancestors. The real difference is that our repeated ancestors are more recent and far more numerous. This endogamy has us all related multiple times even though we may not be aware of it at all.

That is also what creates the illusion that people are closer than they actually are. Two people with several small amounts of matching DNA representing distant cousinhood, may appear to be more closely related because the total amount of matching DNA fits a closer relationship.

Let me repeat, the parties to such marriages are related multiple times through distant cousinhood of which they are probably totally unaware.

This, however, is not the endogamy that the average researcher thinks of when the term first comes up. The average Jewish researcher hears the term "married within the tribe" and says "My (great-)great-grandparents married cousins." To be sure, this too is endogamy, but it is of a different type.

Close cousin marriages
I refer here to marriages on the order of first or second cousins, an uncle and a niece or a first or second cousin once removed. Sometimes a bit more distant. These are generally deliberate choices, whether of the bride and groom themselves or more likely their parents.

These relationships can be useful in analyzing genetic test results. For instance, a person born of a marriage of first cousins will have on average 25% of his DNA from each of the great-grandparents that the parents share.
The percentages below 50% are averages.
That is the same percentage (on average) that each parent has from those same great-grandparents. As a result, for the purposes of examining those two great-grandparents, the child can serve as a stand-in for the parents. His DNA would not be diminished by the additional generation.

The Pikholz Project's most extreme known example of what I would call "personal endogamy" is Leonora, whom I have mentioned here before. Leonora's mother Taube left Skalat as the Germans approached in 1941 when she was eighteen, and fled east, ending up in Tajikistan, where her two daughters were born. All four of Taube's grandparents are Pikholz. Her father's parents are first cousins. Her mother's parents' relationship is more complex. I discuss this family in Chapters Six, Thirteen and others, in my book ENDOGAMY: One Family, One People.

There are a number of reasons for a culture of cousin marriages. Sometimes it was as simple as a small Jewish community with little contact with outsiders. Expanding that circle a bit, we have parents contracting marriages for their children with the people they know best - their siblings and close cousins, people they trusted, people whose life expectations and religious customs were like their own.

Related to that, a man (or a widow) matches his youngest son with his eldest granddaughter. The family provides a perfect shelter for the young couple.

Of course there are issues of business and property. Keeping it in the family by marrying within the family is a time-honored tradition. We see it among royal and other upper-class families and it happened among the regular folks as well. Similar to that is what we often see in rabbinic families, the closest thing to Jewish royalty.

We know of many instances in the 1800s where a woman dies leaving a husband with young children and the family assigns him a new wife either from his own family or from the wife's family. Dwojre, the wife of Simon Pikholz, dies in 1861 at age twenty-three leaving two young daughters. Simon then marries her younger sister with whom he has a string of additional children. (I discuss the DNA of this family in Chapter Thirteen.)

Sometimes those second spouses - "replacement spouses," if you will - are already related. My grandfather's first cousin Sara Frankel was in the US and pregnant with her first child when her husband died. The family back in Skalat sent a cousin of hers to marry her - though we have still not figured just how she and the second husband/cousin are related.

I believe that a similar situation occurred among my own Skalat ancestors, as I discuss in Chapter Twelve.

On my mother's side, after my grandmother's brother lost his wife in the 1940s in the US, his widowed sister-in-law married him so that (according to my mother) some strange woman wouldn't spend his money, depriving her niece and nephews of their rightful inheritance. (I learned four years ago that his children had never heard that explanation!)

When Josef Pikholz of Klimkowce lost his first wife, his children were raised by his second wife who was also his niece. This kind of thing happened all the time. It was part of the social safety net of the era.

Yet another phenomenon was explained by a Lithuanian archivist at a talk at one of the IAJGS conferences eight or nine years ago. (I apologize for not remembering her name or the specifics of her talk.) She was addresssing the question why many marriages took place in towns where neither the bride nor the groom lived. Her explanation, this non-Jewish archivist: "Sheva berachos." The seven days of feasting after a wedding. It seems that during this period, the families would round up all the available young people ("young" meaning anywhere from about twelve years of age) from both families and match them up for additional weddings held there on the spot.

And I haven't even mentioned the possibility that cousins from the same gene pool living in the same place may have been attracted to one another, without the intervention of the parents.

All these cousin marriages create an endogamy that is known to everyone at the time and is recorded in some form in the family tradition, though not always correctly. The grandchildren of Rozdolers Berisch Pickholz and his wife Golde Pickholz always knew that their grandparents are cousins and assumed that meant "first cousins." They are wrong. Second cousins is most likely correct, but third is also a possibility.

The difference
Both these types of endogamy contribute to the difficulty of identifying specific ancestors and the path that any segment of DNA may have taken as it traversed the generations.

But they are not the same. The first kind of endogamy, the one that causes pedigree collapse, represents a dispersal of DNA segments among the ancestral lines of any individual or family. My sixth great-grandmother's DNA comes to me from eight, ten, twelve or more directions, each traversing a different set of my ancestors on its way to me. Good luck figuring them out, identifying the ancestors on each path and the relatives that are generated from each specific path.

What I called above "personal endogamy" is quite the opposite. Instead of diffusion, it creates convergence. My great-grandfather's parents were both Pikholz (we don't know exactly how they are related) so he carries something of a double dose of Pikholz DNA. His Pikholz-ness is more intense. And if there were additional Pikholz cousin marriages in his background - as in the case of Leonora's mother - that intensity is magnified. Although that can make it harder to be precise in our genetic analysis, it can make it easier to do a more general genetic analysis.

If an outsider appears to match my great-great-grandparents who were born two hundred years ago and who are closely related, all we need to know is the match to the family. In any event we usually cannot be so precise as to match the individual. Furthermore, this personal endogamy is strong enough that it smothers the older more diffuse endogamy. It can take what was quite impossible and make it manageable. With the right strategy, that can sometimes be enough.

The results of my great-grandfather's Lazarus kit (Chapter Eighteen) show some of that.

Note: Last week I received Avotaynu's Spring issue, which includes an article by my down-the-block neighbor Zev Kalifon, on the subject of endogamy. I had written this blog post earlier and the two seem to fit together nicely. I will suggest that Avotaynu Online might want to run them together.

Housekeeping notes
I can add to my US speaking tour a joint program of South Suburban Historical and Genealogical Society and Illiana Jewish Genealogical Society, 3000 West 170th Place, Hazel Crest Illinois, on 23 August at 1:30.

That is in addition to
16 August, 1:30 – JGS of Maryland Hadassah, 3723 Old Court Rd., Suite 205, Baltimore

17 August, 7:30 – JGS of North Jersey YMCA, 1 Pike Drive, Wayne NJ

25 August, 7:30 – JGS of Los Angeles, American Jewish University

26 August, 7:00 – Phoenix JGS, Cutler-Plotkin Jewish Heritage Center,
Arizona Jewish Historical Society, 122 E Culver St, Phoenix

30 August, 2:00 – JGS of Long Island, Mid-Island Y-JCC, 45 Manetto Hill Road, Plainview NY

and a couple of others in the works.


  1. Ah, I saw on my matches also,some of these Skalat matches not named Pickholz. I got a new Pickholz in he last couple of days. What I haven't found us where they connect.

  2. I just came across your blog post titled, Two Very Different Kinds of Endogamy. Great explanation. I have a brother-in-law and a sister-in-law who are Acadian and it has been challenging to determine some relationships based upon DNA. Understanding endogamy isn't as difficult as explaining it. I was able to use some of your language and examples to help. Thanks for publishing such a well written piece. Best Regards, Lynn