Most Ashkenazim have difficulty tracing their roots past the late 18th century because, in many parts of Europe, Ashkenazim did not adopt surnames – and Jewish vital records were not maintained – until the 19th century. However, there are some Ashkenazi families – often rabbinical dynasties – with known family trees going back five centuries or more. To the extent that Ashkenazim are able to tie their ancestral lines to a known rabbinical line, they will be able to extend those lines several hundred years into the past.
In recent years, many genealogists have taken advantage of Y-DNA Short Tandem Repeat (“STR”) and Single Nucleotide Polymorphism (“SNP”) testing, which allows the identification of men who share a relatively recent common ancestor on their direct male line. Studies have shown that a substantial proportion of Ashkenazi men - perhaps as much as 13% of the total Ashkenazi population, including more than half of Ashkenazi men with a tradition of a Levite descent share Y-DNA making them part of what has become known as the R1a1a Ashkenazi Levite cluster.
All R1a1a Ashkenazi Levites are descended from a single man who lived about 1,000 to 1,500 years ago. There has been considerable dispute concerning the origins of that man. Some scholars have hypothesized that the R1a1a Ashkenazi Levite progenitor may have originated as a convert in Khazaria or Adiabene; others, questioning how a convert might have assumed Levite status, have hypothesized that the progenitor may have been descended from, e.g., a Jewish tribe in the Near East, perhaps on the Arabian Peninsula, or Persian Nethinim who became assimilated into the Levite population after the Babylonian Exile.
At least 20% of R1a1a Ashkenazi Levites appear to be descended on their direct male line from a single man who lived in about the 15th century. Our analysis shows that man may have been the founder of the Horowitz rabbinical family of Prague.
We seek to tie the burgeoning field of genetic genealogy to traditional paper genealogy. Most Ashkenazim are unable to trace their roots back past the mid-18th century, at the earliest. We seek to show that genetic genealogy can be used, with some degree of certainty, to leapfrog over gaps in the paper trail to tie into known direct male lineages that go back four or five centuries. The methodology and test results that we are developing are of significance not only to descendants of R1a1a Ashkenazi Levites (a substantial number of whom will likely be able to trace their ancestry to the Horowitz rabbinical family), but also generally to men who do Y-DNA testing (who will be able to use the same methodology to identify their own Y-DNA clusters and to tie them to known genealogies).
Second, we hope to clarify – and, perhaps, resolve – the origins of the man who is the direct male ancestor of as much as 13% of the total Ashkenazi population. SNP testing may allow us to determine whether the R1a1a Ashkenazi Levite progenitor was descended from, e.g., Khazarian royalty, a tribe of Levites decimated by the Mohammedan conquest of Arabia, Nethinim from Persia who came to Jerusalem after the Babylonian Exile, or a man who became a Jew near the time the religion was established, making tangible historical migrations that occurred a millennium or more ago. The December 2013 paper by Rootsi & Behar et al., discussed elsewhere on this site, has already done much to address this issue by establishing that R1a1a Ashkenazi Levites share a relatively recent common ancestor with men from the Near East and Levites who are not Ashkenazi. The Y-DNA STR and SNP results that we have gathered and are continuing to gather should provide a basis for expanding on this finding.
Our research is proceeding on two tracks. First, we are seeking to identify and obtain Y-DNA STR test results from men who are known descendants of Levite families with established genealogies going back several centuries in order to determine and confirm the relationships among men who share a genetic link to men of known genealogies. Second, we are seeking to obtain SNP test results for R1a1a Ashkenazi Levite men to identify the Y-DNA SNPs that distinguish subclusters of R1a1a Ashkenazi Levites.
We also hope to use SNP test results from those men, along SNP test results from men in closely related groups, to confirm the SNPs that distinguish R1a1a Ashkenazi Levites from closely related R1a1a groups and to gain further insight into the likely origins of the R1a1a Ashkenazi Levite progenitor.