Medrash tells us how לעתיד לבא (in “the future era”) the kohanim will be authenticated to the level of “kohen meyuchas”- the Rambam says by מלך המשיח while sefer Ezra implies that the authentication process will be done by the kohen gadol and the urim and tumim.
But what about DNA testing? can the test known as Y-DNA12 have a bearing on today’s kohen muchzak in terms of giving him a boost of authenticity?
What it is
The test, called Y-DNA is available for males to discover their patrilineal line heritage, it is provided at geni.com for a fee and promises to “uncover the deep ancestral origin of your direct paternal line (your father, your father’s father, etc.) through Y-DNA testing”.
There, a special group has been started to verify the patrilineal lineage of kohanim, This seems like an amazing technological breakthrough, but what can it do for today’s kohen?
An interesting facet the test may clear up is the known gmara where the kohen Pashchur ben Imar had 400 (or 4000) slaves who where “converged” into mistakenly being labeled as kohanim. Of course, with a bit of legwork, this DNA test could ascertain that any given kohen is not a patrilineal descendant of one of Pashchur’s servants who was not an actual kohen.
What it is not
Although the test clearly promises to provide the patrilineal link of today’s kohen, it may not carry much halachic authenticity regarding the sound חזקה of today’s kohen, since the said individual may be a patrilineal descendant of Ahron HaKohen but still be a challal and thus generally invalid for kehuna work.