HomeNewsEndogamy: Ashkenazi Jewish Case | The Global Today

Endogamy: Ashkenazi Jewish Case | The Global Today

As genealogists we wish to perceive our match lists. We wish to establish the matches that may give us the stable clues we have to make progress on our goal ancestor’s household tree. Endogamy and its shut cousins, pedigree collapse and a number of relationships, complicates that. Diana laid out the definitions within the first blogpost on this collection: “Endogamy, Pedigree Collapse, and A number of Relationships: What’s the Distinction and Why Does it Matter?” Nicole wrote about methods for overcoming endogamy on this submit: Methods for Overcoming Endogamy.

Endogamy refers to when intermarriage has occurred over many generations (centuries) in a neighborhood, whereas pedigree collapse happens in a a lot shorter timeframe. At first I assumed endogamy could be a non-issue for my family analysis (largely Nineteenth century German & Irish immigrants), however then my dad turned out to have a small (3-6%) quantity of Ashkenazi Jewish DNA and I discovered that Eire could also be affected by low stage endogamy too. How does having extra marginal endogamy have an effect on my analysis? Since my family tree has ancestors of various ranges of endogamy (i.e. low for German, average for Irish, and excessive for Ashkenazi Jewish), I’ve wanted to entry these completely different ranges to make progress. I hope to unpack on this submit and the following one my very own takeaway lesson from my expertise: endogamy is on a spectrum.

The Human Household

Within the largest sense all people are endogamous. Sooner or later within the distant previous any human alive right now can have a standard ancestor with another human (that point was about 1000 years ago between people of European descent and about 2100 BC between all people). Due to this fact after we say endogamous, it’s a relative time period (no pun supposed). Some communities shall be usually much less endogamous than others. We’re all human so all of us share loads of the identical DNA with one another, however some communities will share barely extra inside their neighborhood than common. In different phrases, endogamy is on a spectrum.

The upper the endogamy in your neighborhood the less distant ancestors you have got. The less ancestors your neighborhood has, the extra your neighborhood shares equivalent by state or IBS segments. IBS segments are these we and our match share from our frequent distant ancestor, versus matches that we share IBD (equivalent by descent) segments that we every obtained from a standard latest ancestor (as much as 5-8 generations in the past). Endogamous communities can have extra IBS segments, which make extra of our matches seem like extra intently associated to us than they’re.

Endogamy is on a spectrum

I’ve a variety of possible endogamy from my ancestral traces: German < Irish < Ashkenazi Jewish (AJ). My AJ neighborhood probably has the best endogamy right here for a number of causes, however one being a bottleneck about 1000 years ago. Why would Germans most likely have the bottom endogamy of those teams? I wrote about this in “Tracing Your Nineteenth-Century German Ancestors: DNA” (see Determine 2), however primarily folks from central Europe have usually skilled better inhabitants mixing than extra geographically remoted communities. Which means that the common German ancestor probably had extra distant ancestors than the common Irish ancestor. Within the subsequent submit I’ll write extra about Irish “endogamy.”

Two components complicating my household’s endogamy:

   1. Incomplete household timber make it laborious to know which matches a DNA tester shares a latest frequent ancestor with (IBD) and which don’t (IBS). AJ have confronted super upheaval, took surnames later, and so will be laborious to hint previous the mid-Nineteenth century (my dad’s Third-4th nice grandparents would have been born earlier than that). Due to this fact discovering the place my household and an AJ match join on paper could also be particularly tough.

   2. Germans are inclined to not take DNA checks, and so my dad’s Nineteenth century non-endogamous German traces can have few matches to start with. The truth that thus far Germans as a bunch have a low charge of taking DNA checks means German endogamy will simply be more durable to run into.

Regardless of the 2 caveats above, we will estimate that some communities can have extra IBS segments than others. Does this imply Germans don’t have any stage of endogamy? No, folks with a German ancestor from a small village will probably share IBS segments with others from the identical village and can seem like nearer kin than they’re. Nonetheless, Germans with IBS segments from the identical village will probably share these with fewer matches, as a result of their IBS segments are much less widespread within the descendants of individuals from German lands than folks whose ancestors have extra endogamy (fewer distant ancestors), such because the Amish.

my largely German dad’s match listing illustrates a few of the foremost ideas of how endogamy impacts DNA evaluation. My dad has a small however important quantity of Ashkenazi Jewish (AJ) DNA (3-6%) that stays constant over many updates over a number of DNA testing corporations. I hypothesize that considered one of his seven Nineteenth century German immigrant nice grandparents could have been about ¼ to ½ AJ. There’s a massive distinction between how his non-endogamous (German) versus his extra endogamous (AJ) ancestry reveals up in his match listing.

Endogamous vs. Non-endogamous communities at

My dad’s Autocluster chart illustrates what I imply. He has loads of AJ matches relative to his matches from non-endogamous traces. I’ve hypothesized that my dad has about an AJ Third to 4th nice grandparent, and if true, that ancestor from an endogamous neighborhood dominates his cluster chart beneath. Filtering for ethnicities at, I discover that 20% of his matches have some AJ ethnicity, additional indicating that his 6% AJ neighborhood claims a disproportionate variety of my dad’s matches.

My dad’s first 10 (30 complete) clusters. Settings: between 25 cM-400 cM, 25 cM minimal threshold.

I’ll put aside the second cluster as a result of it’s over the recognized pile-up area on ch. 9 (38.3 Mbp- 72.6 Mbp) from his one colonial German (“Pennsylvania Dutch”) 2nd nice grandma. After that I notice that the massive first cluster (pink) plus a number of others (yellow, mild blue, darkish blue, brown) are AJ matches between 15-37 cM on the far finish of ch. 16- a possible pile-up area (illustrated beneath). You may see the pretty massive numbers of matches which might be part of multiple cluster (grey bins) are related to my dad’s AJ clusters- a standard phenomenon with endogamy. The truth that my dad’s largest clusters are probably pile-up areas illustrates his scenario (and the necessity to be careful for pile-up areas). His endogamous neighborhood is overrepresented. His non-endogamous German traces should not have quite a lot of matches usually (besides the great-grandma from Baden within the final peach cluster) and so have a tendency to not kind clusters regardless of my dad having extra of those ancestors.


The precise finish of chromosome 16 at a few of my dad’s many matches had been painted, plus his 23&Me Ashkenazi Jewish Ethnicity.

The above DNAPainter screenshot of the suitable finish of ch. 16 I bought by first portray my dad’s ethnicities from 23&Me. To get the ethnicity CSV information from 23&Me: Begin on the high of the 23&Me house web page > “Ancestry & Traits” on the high > “Ancestry Composition” > “Scientific Particulars” > scroll right down to the underside of the web page for the “Obtain Uncooked Knowledge” button > copy & paste CSV information in the identical means you’d with a match’s knowledge into DNAPainter. After that I painted my dad’s greatest matches from I discovered my dad’s AJ matches by utilizing the filtering instrument at On the “DNA Matches” web page, I chosen “Filters” > “Ethnicities” > “Ashkenazi Jewish,” then I chosen “Kind By” > “Largest Section.” This gave me a fast solution to filter for my dad’s AJ matches, which I may subsequent establish one of the best of those by the standards listed within the subsequent part. 

What’s the technique for clearly endogamous populations such AJ?

  1. Discover pile-up areas. De-emphasize these pile-up matches, besides maybe these matches that share an extended phase (a minimum of 20-23 cM) that extends effectively past the pile-up space.
  2. Choose matches you share probably the most DNA with mixed with the longest phase. A number of AJ DNA specialists suggest eliminating matches whose longest phase is beneath 23 cM, and never counting any segments within the complete beneath 10 cM.
  3. Construct household timber of those prioritized matches. Discover any frequent areas (birthplaces) first, then surnames.


I notice that it will likely be difficult to establish my dad’s mysterious AJ ancestor, as a result of AJ mid-Nineteenth century information and older turn into particularly tough to seek out because of the neighborhood’s historical past of compelled dislocation and late adoption of surnames. For a number of causes not essential to this subject, my idea now could be that my dad’s nice grandma from Bavaria could also be partly AJ. A few of the higher AJ matches (i.e. longer segments, non-pile-up segments) have ancestors from Bavaria. Different non-AJ matches on this great-grandma’s line additionally come from the identical particular place in Bavaria. My subsequent steps shall be to seek out extra information on this nice grandma’s line within the U.S., after which hopefully in Europe. I’ll then begin constructing a few of these attention-grabbing matches’ timber extra absolutely.

I hope my dad’s case has illustrated how endogamy can improve the variety of matches, particularly when the tester’s different ancestral traces are comparatively non-endogamous. With my dad’s endogamous line, I must be extra cautious about pile-up areas. Endogamy means it will likely be tough to establish the matches that do share a latest frequent AJ ancestor with my dad, however it’s price a attempt. Within the subsequent weblog submit, I hope to proceed as an instance how endogamy is on a spectrum with a neighborhood with probably average endogamy- the Irish.

Be taught Extra

To be taught extra about utilizing DNA proof in your family tree analysis, you may additionally need to enroll in the Analysis Like a Professional with DNA impartial examine course. On this course, Diana Elder, AG, Nicole Dyer, and Robin Wirthlin take you step-by-step by organizing and analyzing your matches and making use of DNA proof to targeted analysis questions.


  1., “Endogamy, Pedigree Collapse, and A number of Relationships: What’s the Distinction and Why Does it Matter?,” 2 Sep 2022, Diana Elder ( accessed 21 Oct 2022).
  2., “Methods for Overcoming Endogamy,” 5 January 2023, Nicole Dyer ( : accessed 17 Jan 2023).
  3., “What number of distinctive ancestors do you have got?,” 11 Aug 2014, Roots and Routes, ( : accessed 21 Oct 2022).
  4., “The time and place of European admixture in Ashkenazi Jewish historical past,” 4 Apr 2017, James Xue, et. al.,( : accessed 21 Oct 2022).
  5. Weblog.Kitty, “Extra on Ashkenazi DNA,” 23 Mar 2021, Kitty Cooper, ( : accessed 21 Oct 2022).
  6. Woodbury, Paul. “Coping with Endogamy,” Legacy Household Tree Webinars, 14 Oct 2020, ( : accessed 18 Sep 2022).
  7. Ferretti, Alec. “Methods for Analyzing Endogamous DNA, ” 12 Jun 2022, handout ( : accessed 21 Oct 2022).
  8. Lara’s Jewnealogy, Diamond, Lara, “Ashkenazi Shared DNA Survey- September 2019 Replace,” 1 Sep 2019, ( accessed 21 Oct 2022).

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