Semantically the concept of "Pure" for almost any nationality is almost impossible and the more diverse the population, the less the possibility that anything can be "pure." I would however think that one could say that regardless of roots, certain genres eventually are so associated with one country or region as to be a class of their own and thus associated with a particular country or region....and in that sense they are pure. I think a better term is needed, what I have no idea though.

Spaw