The Shaltiels, Charlaps and Dayan families trace themselves back to King David. But if it seems simple, it's anything but. Although the first 20 generations of kings are detailed in Kings and Chronicles, the biblical record stops after the Babylonian conquest of Israel. From there, scholars and genealogists rely on lists of exilarchs. But different lists have different names, and list comparison has been fodder for debate for centuries. Few lists clearly match, with the exception of two: Rabbi Moshe Dayyan's 1879 list is similar to a list found in the Cairo Geniza, says Dayan, referring to the findings of a 2006 scholarly paper written by the late historian David Kelly in the journal of the Foundation for Medieval Genealogy. But like everything else in the field of Davidic genealogy, there are plenty of opinions about what this means, and little agreement.
Enter the relatively new science of genetics, which has added a dimension to the study of the Davidic line. Unfortunately there is no way to take a sample of King David's DNA—no one knows where he is buried—so the only current scientific method of tracing the line is to search for similarities in the male Y chromosome, which passes largely intact from father to son, except for minor mutations, which are what allow scientists to track and identify genetic branches. This was the method used by Karl Skorecki, a kidney specialist at the Rappaport Faculty of Medicine at the Technion Institute in Haifa in 1997, when investigating the validity of the oral tradition of the patrilineal inheritance of the Jewish priestly class, known as the Cohanim. The study found that 48 percent of Ashkenazi and 58 percent of Sephardi men who identified themselves as Cohanim, based on oral tradition, carried a unique chromosomal marker, called the J1 Cohen Modal Halpotype.
To find a unique chromosomal marker shared by men who believe they are descended from King David, it is necessary for two who don't know they are related to each other to have matching chromosomal markers. "If I can find someone from Baghdad community, who is somewhere on the line of the exilarch, and a European Jew who has a similar claim, and these families haven't had contact for hundreds of years, if these two men have the same Y chromosome, I would have to take that as very successful," says Bennett Greenspan, president and CEO of Family Tree DNA, which has conducted some of the Davidic studies.
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