The priestly caste of Jews - called Cohanim in Hebrew - have recently been conducting DNA tests to see whether or not they are actually linked to Aaron, the brother of Moses, as written in the Jewish Bible.
This arose when a tribe in South Africa, known as the Lemba, wanted to find out more about their heritage. Claiming they were Jews because they followed dietary laws similar to those of Kashruth, scientists in England decided that they could perform DNA tests of Jews who claimed to be Cohanim and the Lemba to see if there were any similarities in the readings.
Because neither Aaron's nor Moses' grave are to be found, as written in the last chapter of Deuteronomy, the scientists had to figure out how they were going to go about proving this. They decided to collect DNA samples, through blood testing, of males of all religious faiths and of all nationalities, number them on the sample and a separate piece of paper. The paper was the only place where it was recorded if the sample was from a Jew or not, and if the Jew was a Cohain.

     Before moving on, the average non-Jew should know a little Judaic history. Judaism is divided into twelve tribes or castes. Today, only three remain: the Cohanim, the Levites, and the Yisroëls. Until recently, men and women were not considered equal (and are still not by Conservidox, Orthodox, Lebovitch, Satmar, and Hasidic Jews), making the prestige of the Cohanim only pass through males. For this reason, the Cohanim DNA reading is believed to be found in the Y-chromosome.

     Since the scientists needed to perform many tests with the DNA samples, they copied the strands by using the Polymerase Chain Reaction (PCR). PCR is a procedure in which the DNA is doubled by the addition of primers, which attach themselves to the DNA strands, expand and then separate. The actual testing was done using a procedure known as DNA typing. DNA typing is a multi-step procedure that starts out with a sub-procedure known as Restriction Fragment Length Polymorphism (RFLP). RFLP's splice the strands by using restriction enzymes. The cut up strands are then loaded into gels and subsequently migrate across the gels through a process known as electrophoresis. Matching DNA will show a mark at the same "level" on the gel.

     After conducting these tests, it was revealed that of all the people who claimed to be Cohanim, slightly over fifty percent had the DNA mark. None of the non-Jews who participated had the mark. Of all the Jews, slightly under ten percent had the mark, supporting the Jewish belief that only ten percent of the population were descendants of Aaron. Surprisingly, among the leaders of the Lemba tribe, fifty percent had the mark and ten percent of all the Lemba had the mark as well.

     However, the forensic investigations did not stop there. The Lemba claimed that they originated from a city called Senna, which is believed to be in modern day Yemen. The scientists sent out a group of anthropologists to Yemen. The anthropologists, finding a similarity between the name Senna and the name of Yemen's capital, Sana'a, they started their journey off in this city. That was to no avail until they came across an Arab scholar, who said that Senna was a few miles out of Sana'a. During the visit, they met a certain tribe of Muslim inhabitants of Senna who had the same last names - such as Sulimani - as the Lemba tribe. Historically, there was always a large Jewish community in Yemen until the creation of the modern day State of Israel in 1948. Because of interracial marriage and the fact that Jews and Muslims had a fairly good rapport until the twentieth century, it is quite possible that the Lemba did originate in Senna and that they are Jews.
Since the testing began and it revealed a distinct possibility that these South Africans are Jews and that more than half of the people claiming they are Cohanim have the same recurrent gene, the Lemba are learning Hebrew, acquiring Torahs, and the leaders are studying to become rabbis. In the rest of the world, testing is on going for people who are not sure to which one of the three remaining tribes they belong.