I thought the Kurds were the descendants of the ancient Medes and therefore Indo-European. But since the Ten Lost Tribes were initially exiled by the Assyrians (northern Mesopotamia) then I suppose they left some genetic evidence behind. I'm not comfortable with the whole "lost tribes" ideology, however.
As far as the lost tribes go, Simha Jacobovici (local Toronto academic & filmaker) had an interesting take on the subject in a two hour documentary called Quest for the lost Tribes. Controversial, but certainly worth a look. Josh Bernstein (digging for the truth show) had a nice presentation in one episode on the Lembe - a bit lightweight, but worthwhile.