The Jewish faith and customs stretch back more than three thousand years, connecting lives today with their ancient roots. But genealogically establishing that connection has its challenges.
This article explains how modern DNA testing and genetic genealogy can help. We recommend testing with Family Tree DNA.
Judaism is a Religion
Ethnicity is generally defined by people who have shared ancestors and live in a common area.
But Judaism is a religion that anyone can adopt, and many people have done so.
So what do we actually mean when we talk about Jewish ancestry and a “Jewish DNA test”?
We’re talking primarily about three groups of people:
- Ashkenazi Jews who settled first around France and Germany, and many of whom later moved to Eastern Europe.
- Sephardic Jews who settled in Spain and Portugal, then later migrated to Southern Europe, North Africa, the Levant, and Anatolia.
- Mizrahi Jews – descendants of those Jews who originally remained in Babylon before spreading out across the Middle East and Southwest Asia.
Even though they lived among other ethnic groups, the Jews were largely segregated and had limited intermarriage with the local populations.
As a result, they maintained their genetic distinctiveness from those around them.
Because each of these three jewish communities was separated for centuries, they each developed distinct genetic heritages from one another as well.
DNA Testing for Jewish Roots
While any of the three types of DNA testing can help to establish Jewish ancestry, some are more useful than others.
Mitochondrial DNA (mtDNA)
An mtDNA test, which examines pieces of DNA that are passed down directly from a mother to her children, can help identify Jewish ancestry in many cases.
Four haplogroups are found almost exclusively among Jews.
If you belong to one of those haplogroups, then you almost certainly have Jewish ancestry somewhere in your maternal line.
However, only about half of all Jews belong to those haplogroups, so if you belong to a different haplogroup, it does not rule anything out.
Passed down directly from father to son, Y-DNA can help you connect with a direct male line that may stretch back dozens of generations.
If you can connect with an established ancestor linked to other researchers, this can be a tremendous help to finding both your roots and your living relatives.
Some Y-DNA testing companies offer different kits that test fewer or more genetic markers.
The more markers that get tested, the better your results are going to be. Even though it is more expensive to test more markers, it is usually well worth the cost.
While a few testing companies offer basic Y-DNA testing, Family Tree DNA is the only company to offer dedicated Y-DNA tests.
An autosomal DNA test is best for connecting you with living relatives who can help you focus and extend your research.
But if your Jewish ancestry is more than five or six generations back, an autosomal DNA test is not likely to provide much information when it comes to linking to that ancestry.
Family Tree DNA has an autosomal test called Family Finder.
Read our complete guide to the best DNA test kits.
Benefits and challenges of DNA testing
There are several ways that genetic testing can provide crucial clues for your Jewish ancestry search.
But there are certain challenges as well.
People change their surnames for many reasons.
The most common is when moving to a new country, such as those who arrived in England or the United States who chose to change their surnames to match local names better.
Some Jewish families changed their surnames to avoid persecution as well.
When surnames change, it makes your research much harder. If your grandfather chose one new surname, and his brother chose a different one, finding your living relatives can be almost impossible.
However, an autosomal DNA test is perfect for finding living relatives, whatever their surnames.
A Y-DNA test can also link you to a surname project that will help you trace your family back to its original name.
Lack of genealogical records
The government collection of birth, death, and other records is relatively recent, in some areas not going back much more than 100 years.
Many other records have been lost or destroyed.
This can hold especially true for any Jewish family that was forced to move to a new country.
If these records do not exist, DNA testing may be the only way to pursue your family heritage.
Even while living among other ethnic groups, the Jewish people remained isolated.
Marriage with outsiders was rare compared to other groups. As a result, many genetic traits became reinforced over time.
What that means today is that two people of Jewish descent may have more genetic markers in common than usual, even if they are not closely related.
This can throw relationship calculators off by one to two generations.
As a result, someone the relationship calculator says is your second cousin may, in fact, be a third or fourth cousin.
That can make figuring out how your family trees line up more difficult.
The opposite problem of cultural isolation, the Jewish Diaspora spread Jews across many parts of Europe, Africa, the Middle East, and Central and South Asia.
While most ethnic groups are identified by where they lived, Jewish groups are identified by how they lived.
But even with limited contact with local ethnic groups, there was some contact and some intermarriage.
As a result, traces of those other groups run throughout the genetic heritage of their descendants.
While certain haplotypes are almost exclusive to those of Jewish descent, as many as half of all Jews do not belong to those haplotypes.
So if you have a very strong Jewish ancestry, your mtDNA or Y-DNA test might show that, but it might not, too.
Certain haplogroups are rarely found except among people with Jewish ancestry (read this article on how to find your haplogroup for more on this).
Jewish population genetics tells us that mitochondrial DNA haplogroups K1a1b1a, K1a9, K2a2a, and N1b, for example, are common among Ashkenazi Jews but rarely seen in anyone else.
Common Y-chromosome haplogroups include J (and its subgroups) and E1b1b.
Belonging to one of these haplogroups is a reliable indicator of Jewish ancestry.
Because the Ashkenazi, Sephardi, and Mizrahi Jews separated long ago, there has been time for the groups to drift apart genetically.
This means that a genetic test can not only identify Jewish ancestry but can often tell you the specific group.
That can help narrow down your research to the part of the world where they lived.
DNA testing can be useful for any family history search, but especially so for researching your Jewish roots.
Surname changes and missing records can make tracing your Jewish ancestry difficult.
While DNA testing has some limitations, it can still be a tremendous help in confirming your ancestry and building out your family tree.
It can help you narrow your search, and connect you with living relatives who may have information vital to your search.