[okie01]

but I'm sure that if a simple 'mouth swab' for Jewishness was ever developed and marketed it'd open up several cans of worms.

Osama bin Ladenstein...

[cambridge]

Exactly, among other things. I recall DNA research linking Palestinians to Israelis:
http://www.khazaria.com/genetics/abstracts.html
[Which also contains this interesting line : "Many Spanish-speaking Latinos of the American Southwest are descended from Anusim (Spanish Jews who were forced to convert to Catholicism)"]