Today, we live in an age in which it is possible to know the paternal and maternal lineage of any person alive- or dead. While in former times, this was accomplished by genealogical records- which could be altered or forged- today, the technological advances in genetics provides proof positive- which cannot be altered or tampered with. Why is it so important to utilize this technology?
According to the Torah, an Israelite is a descendant of Jacob- the son of Isaac, the son of Abraham. The Torah recognizes only paternal descent [through which inheritance passed]- except in the case a man has only daughters. In that case, those daughters must marry within the paternal line of their father- thus preserving the paternal line [Numbers 26-27; 36]. Another exception to the rule of inheritance is in the case a man died without having a male to preserve his line; in that case, the brother was to marry the wife of the dead brother and produce an heir for his dead brother [Deuteronomy 25:5-10].
The fact that the Israelites have been spread out into the world, conquered and enslaved, intermarried among the various nations- having their paternal line destroyed by Rabbinic decree that ethnicity is maternal- is reason enough to use DNA testing to prove the paternal lines of the Israelites.
Among those claiming Israelite ancestry, there are the following paternal [Y Chromosome] lineages:
Haplogroup J; Haplogroup E; Haplogroup G, and Haplogroup R- with various other paternal haplogroups represented in minute amounts such as Haplogroup Q, and Haplogroup T.
If we accept that there was indeed men named Abraham, Isaac, and Jacob, then there must be a single paternal lineage for all Israelites today. It is important, then, for us to acquire a DNA sample from the Israelites which were buried in Israel- specifically the lines of the Kings and Priests [Kohanim]. Descending from the same man, they would have the same paternal haplogroup- all branching from the same male. This would, then, settle the debate as to the true lines of the Israelites. While the thought of disturbing the graves of our ancestors is a taboo, there is nothing in Torah which would make it a violation to do so; in fact, the Israelites took the bones of Joseph with them when they left Egypt.
Below is an example of a Y Chromosome Paternal lineage of Israelites. I am working on notating other paternal haplogroups as well- stay tuned.
The Y Paternal lineages of modern Lebanese demonstrate that the Lebanese descended from the same lines as modern Israelites