You've been learning about genetic genealogy, and perhaps have found a few new distant cousins or at least possible cousins. Where might you go from here? Can you also use your DNA test results in new ways? There are many directions you can follow, depending on your personal interests. On this page you'll find links to topics and resources that might intrigue you.
- Intermediate Genetic Genealogy Topics
- Jewish Genetic Genealogy
- Surname and Location Projects
- Y-chromosome DNA Testing
- Mitochondrial DNA Testing
- Admixture & Ethnicity
- Genetic Diseases & Trait Analysis
- Advanced Genetic Genealogy Topics
- DNA Segment Analysis
- Genetic Anthropology
- Genome-wide Association Studies
Intermediate Genetic Genealogy Topics
Jewish Genetic Genealogy
Jewish genetic genealogy is like other genetic genealogy but with a few additions and complications. The main complication is "endogamy," which is the cultural custom of marrying within a group. The genetic genealogical consequence is that there is a higher baseline amount of DNA in common between Jewish people than among a random group, and this appears very strongly in the Ashkenazi Jewish population.
DNA matching to find relatives is based on the amount of shared DNA. The practical result of endogamy for Jewish genetic genealogy is that most of the people that DNA testing typically suggests (based solely on the amount of DNA in common) are 3rd cousins are usually 4th-6th cousins. Even many or most predicted 2nd cousins are actually 3rd-5th cousins.
Because of endogamy, additional information is very important for screening matches to identify closer relatives. This can include finding shared surnames, geographical matching of ancestral birthplaces, comparing family trees, traditional genealogical documentation, and considering the size of individual matching DNA segments rather than just their combined total length.
- Science News
- Ashkenazi DNA: We are all descended from 350 people in medieval times. Kitty Cooper's Blog, 10 Sep 2014.
- Galitzianer-Litvak divide: Demolished by Y-DNA studies. Avotaynu Online (website), 1 Oct 2007.
- No, you don’t really have 7,900 4th cousins: Some DNA basics for those with Jewish heritage, by Jennifer Mendelsohn. Medium (online magazine), 23 May 2017.
- Is AncestryDNA helpful for Jewish genealogy? by Jasmine Rockow. Ancestry.com Blog, 21 Jul 2017.
- Using Ashkenazi Jewish DNA to find family, by Kitty Cooper. Kitty Cooper's Blog, 10 Nov 2014. Jewish genetic genealogy requires more work then other genetic genealogy, and can lead people who mostly deal with non-endogamous populations to be somewhat pessimistic. But success stories are common!
- Why autosomal DNA test results are significantly different for Ashkenazi Jews, by Paull J.M., Tannenbaum G.S., Briskman J. Avotaynu (magazine) Vol. XXX, No. 1, Spring 2014.
- Ashkenazi Jews are not inbred, by Razib Khan. Discover (magazine), 20 Jul 2012.
- Practical Experiences
- Aunt Shaindel was lost—and found (A DNA success story), by Lara Diamond. Lara's Jewnealogy (blog), 19 Jun 2013.
- Jewish genes as time machines, by Nadine Epstein. Moment (online magazine), 7 Sep 2016.
- It happened to me: I found out I'm Jewish in my mid-twenties, by Danielle Austin-Herb. XOjane (online magazine), 8 Feb 2016.
- When family stories are proven correct—Backed by DNA, by Lara Diamond. Lara's Jewnealogy (blog), 3 Dec 2017.
- All My Foreparents (blog), by Israel Pikholz. Many relevant posts. Includes some rather advanced (but excellent) material.
- Dealing with endogamy, Part I: Exploring amounts of shared DNA, by Paul Woodbury. LegacyTree Genealogists (website). Part 2 is here.
- The faces of endogamy, by Roberta Estes. DNAeXplained (blog), 20 Mar 2017.
- Endogamy in practice: Updated, by Lara Diamond. Lara's Jewnealogy (blog), 29 Mar 2017.
- Endogamy: A closer look (part 1), by Lara Diamond. Lara's Jewnealogy (blog), 7 Sep 2017. Also part 2 (13 Sep 2017) and part 3 (19 Sep 2017). This is somewhat more advanced material.
- Endogamy. International Society of Genetic Genealogy (ISOGG) Wiki.
- Legacy: A Genetic History of the Jewish People (book), by Harry Ostrer. 2012. Note: Slightly dated. (TPL)
- Abraham's Children: Race, Identity, and the DNA of the Chosen People (book), by Jon Entine. 2007. Note: Somewhat dated. (TPL)
- Jacob's Legacy: A Genetic View of Jewish History (book), by David B. Goldstein. 2008. Note: Somewhat dated. (TPL)
- Endogamy: One Family, One People (book and website), by Israel Pickholtz. Note: This book is heavy on the practical aspects of dealing with endogamy in genetic genealogical work.
Surname and Location Projects
... To be added....
Y-chromosome DNA Testing
The human Y-chromosome (Ychr) is only found in males, who receive it from their father. Therefore, it serves as a genetic marker for the patrilineal (direct paternal) lineage. Because the Y-chromosome is preserved intact with each generation, in contrast to other chromosomes, it can be used to trace lineages back hundreds, thousands, and even tens of thousands of years. Population migration studies based on modern and ancient DNA show that most Jewish men have Y-chromosomes that come from the Middle East.
A particularly interesting situation arises around the Kohanim priesthood tradition in Judaism, which is passed down paternally and is traditionally said to derive from Moses's brother Aaron as told in the Torah. If the only source of new Kohanim were patrilineal descendants of one historical man, then all modern Kohanim would share the same Y-chromosome. They do not, but there are a few Y-chromosome "clans" that are particularly common among today's Kohanim. This suggests that a small number of men in ancient times formed the original Kohanim, but there may have been a few new "adopted" lineages added since then.
- Tip of the iceberg: What Y-DNA lineages can tell us about Jewish history and migration. Avotaynu Online (website), 26 Aug 2016.
- Y-chromosomal Aaron. Wikipedia.
- Y DNA matching and connecting with your paternal ancestor, by Roberta Estes. DNAeXplained (blog), 14 Apr 2016.
- Paternal lineage, Y chromosome, in Genetic studies on Jews. Wikipedia.
- Y-DNA haplogroups. Geni.com project.
- Catalogue of Y-DNA Jewish branches. JewishDNA.net.
Mitochondrial DNA Testing
Mitochondrial DNA (mtDNA) is found in both males and females, but children only inherit mitochondrial DNA from their mother. Therefore, mtDNA serves as a genetic marker for the matrilineal (direct maternal) lineage. Like the Y-chromosome (Ychr), mtDNA is preserved intact across generation, and therefore can be used for deep ancestry studies. However, it mutates much more rarely than the Ychr, and therefore has limited use within a genealogical timeframe (the most recent 500 years).
Population studies have shown that most mtDNA of modern Ashkenazim originated from Europe and not the Middle East around and before the time the Ashkenazi population was founded roughly 700 years ago. Given that the Ychr of most Ashkenazi men comes from the Middle East, we can conclude that the Ashkenazi population was mostly founded by Jewish men who migrated from the Middle East and married native European women. Some modern Ashkenazim do carry mtDNA with a Middle Eastern origin, so there were some Middle Eastern Jews who immigrated to Europe as families around or before the time of the Ashkenazi founding.
- Millions of Jews traced to four women: Study identifies genetic signatures for 3.5 million Ashkenazi Jews. ABCNews.com, 12 Jan 2006. Originally from Associated Press, also online here. NOTE: The Ashkenazim were founded by around 175 women, but many of those were descended matrilineally from the same four women, and their descendants are also particularly well-represented in the modern Ashkenazi population.
- Ashkenazi Jewish matrilineages mainly of European origin. Dienekes' Anthropology Blog, 8 Oct 2013.
- DNA testing for genealogy – Getting started, Part Two: Mitochondrial DNA, by CeCe Moore. Geni.com Blog, 2012 Jul 25.
- Maternal lineage tests. Family Tree DNA Beginner's Guide.
- Maternal line: Mitochondrial DNA, in Genetic studies on Jews. Wikipedia.
Admixture & Ethnicity
Is there such a thing as Jewish DNA? Sort of. Does having "Jewish DNA" make you Jewish? Nope. What does "Jewish" mean in a genetic genealogy ethnicity report anyway? It's complicated.
It is conceptually useful to separate the religion of Judaism from the ancient and modern tribal population of the Hebrew people. Jewish religious identity has absolutely nothing to do with DNA—nothing about your DNA makes you a Jew or not.
Genetic identification as a member of the Hebrew tribe in general is complicated by the influx of non-Hebrews through conversion and marriage during the past several thousand years. However, the endogamy and historically low intermarriage rate of Ashkenazim in particular has resulted in a well-defined set of genetic markers that reliably identify members of this specific population and their recently intermarried descendants.
Although Ashkenazi DNA can be reliably identified when present in at least moderate amounts (>5%), Sephardi, Mizrahi, Ethiopian and other segments of the world Jewish population are more challenging. Only some DNA testing companies currently attempt to distinguish those other sources of DNA, but more may in the future as the number of tested members from each sub-population grows.
- Unraveling the science behind ethnicity estimation. Ancestry.com Blog, 24 Oct 2013
- Ethnicity testing: A conundrum, by Roberta Estes. DNAeXplained (blog), 10 Feb 2016.
- Genetic testing raises an age-old question—Are the Jews a people, or a religion? by Mayrav Saar. New York Post (newspaper), 13 Jun 2013.
- Ashkenazi Jews. Wikipedia.
Genetic Diseases & Trait Analysis
There is a common misconception that Ashkenazi Jews have a much higher frequency of genetic disorders than other populations. This is not true. The misconception arose mostly because the Ashkenazi community has frequently been selected for biomedical research studies because it is well-defined genetically, is a fairly large population, shows a few diseases that serve as useful models for genetic disease in general, and is culturally amenable to scientific research.
Like all well-defined genetic populations, Ashkenazim carry some heritable diseases whose causative genes are more common than in other populations. But there are other genetic diseases that are less common. In addition, the highly publicized program to identify carriers of Tay-Sachs disease resulted in plummeting numbers of new Tay-Sachs cases, and may lead to the near elimination of this disease from the Ashkenazi population within a few more generations. Other genetic diseases of Ashkenazim may similarly follow.
- The role of the Jewish genealogist In medical and genetic family history. Avotaynu Online (website), 1 Sep 2016. Originally publication: Avotaynu (magazine), Spring 2007.
- How Jewish activism has virtually wiped out Tay-Sachs, by Ira Stoll. Times of Israel (newspaper), 23 Aug 2017.
- Medical genetics of Jews. Wikipedia.
- Promethease, free health and other trait analysis.
Advanced Genetic Genealogy Topics
Sections to be added...
- DNA Segment Analysis
- Genetic Anthropology
- Genome-wide Association Studies