The Challenges of Jewish DNA testing

By Kitty Munson Cooper
Blogging at

23 pairs of chromosomes

Image of painted (SKY) chromosomes - Courtesy of DeWitt Stetten, Jr., Museum of Medical Research

Questions people hope to answer with DNA testing are:


Where are my ancestors from?

Do I have any unknown relatives out there?

Am I related to ... those other ENGELs (or Schwartz or other family name)?

Three types of personal DNA tests

Y test for father's father's line

mtDNA for mother's mother's line

Autosomal DNA test for all your ancestors

Where to do an Autosomal DNA Test if you are Jewish?

My recommendation:

Test at 23andme and then upload those results elsewhere, that gets you high level haplogroups and some health results

  • Upload those results to Family Tree DNA, MyHeritage, & GEDmatch

If you can afford it also test at 

  • Problem: Ancestry removes population specific segments giving better matches but it is least likely to have matches for recent immigrants. It has the largest database and good tree matching.

If you can afford it also do Y testing of your male line(s) at Family Tree DNA. Start with the 37 marker STR test.

Diagrams from the NIH

SNP - Single Nucleotide Polymorphism

a DNA mutation where a single letter chang3s


STRs are short tandem repeats


An extra copy is made of a sequence of DNA

An extra copy is made of a sequence of DNA

An extra copy is made of a sequence of DNA

An extra copy is made of a sequence of DNA


An extra copy is made of a sequence of DNA


2 Types of Y DNA Tests

Deep ancestry - haplogroup

More recent ancestry - surname studies

Y Haplogroups from SNPs

Jewish Y Haplogroups: J1c3, J2a Cohanim
R1a1 most Levites
E1a1 is frequent
Others: various J subgroups, T1, and E1b

Sample Y DNA results at 67 markers for a Jewish man

Not a single surname in common among these close matches

Jewish E haplogroup Family Tree DNA project

A project at Family Tree DNA for Jewish Y markers

Mitochondria under a microscope

Jewish mtDNA


Near Eastern origin mtDNA Haplogroups:
K1a9 and N1b2


others are H variations, probably European


Your autosomal DNA results are about 700,000 lines of data in a spreadsheet

Inheritance from 8 g-grandparents,
courtesy of Angie Bush Ethnicity

Ethnicity Estimates for half Galician half Polish Jewish Person Estimate

Ethnicity Estimates for half Galician half Polish Jewish Individual estimate for the same person: left tested there, right uploaded

The problem with Jewish Autosomal DNA matching is that we are all related!

MyHeritage Matches for our Galician and Polish Jewish person

You do not need to look at all those matches!


Start with the low hanging fruit, "extended family" estimated 3rd cousins or closer and large segments

Enter the cMs and get probable relationships

Lara Diamond is collecting Ashkenazi data and her preliminary report is here:

Close relationships are within the normal range but at the high end, the average is about 100-200 cM larger than the norm

Kitty's Guidelines for Jewish DNA Matches worth following up on

  • At least one segment > 20 cM
  • Another segment > 10 cM
  • Several more good sized segments
  • Sort by the largest segment

Match to a maternal side Ashkenazi 3rd cousin

Comparison to a paternal side Norwegian 3rd cousin

Clustering tools often create one big blob for Ashkenazi Jews - this one used the range 90-250 to get past that

has not yet been useful

MyHeritage is the best place to work on Jewish DNA matches

Theory of Family Relativity for Steven and Stanley

Some of the items on the DNA match page for Steve and Stanley

The shared matches shows how they are related to each of you!

The MyHeritage Chromosome Browser lets you see a map of the DNA segments where you match.

Plus the segments which triangulate are outlined!

23andMe will also show how the shared matches are related

Getting New Cousins to Respond to You

  • Have a family tree online
  • Upload friendly picture of yourself
  • Include details of who matches whom (they may have multiple kits)
  • Offer them information when you write to them

Do not be disheartened by lack of responses, some rarely log in 

Aunt Shaindel is found!

Israel Pickholtz documents his extensive family DNA project

There is lots more information on my blog about Jewish DNA for example, read

Challenges of Endogamy: Jewish DNA testing 2021

By Kitty Cooper

Challenges of Endogamy: Jewish DNA testing 2021

Working with DNA testing presents unique challenges to the Jewish genealogical community due to the close relatedness of their DNA and the lack of deep family trees

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