[chrisco255]

The idea of pure cultures is even dumber. One is genetically traceable, the other is fluid and depends more on family upbringing and influence from local population interactions and social networks and mass media exposure. Unless Zapotec has remained uniquely isolated from quite strong Spanish/Mexican cultural identity and influence.

[OJFord]

But it's also like, we know what we mean, if the Zapotec people/community are fairly insular or at least in marriage/procreation like to be with their own then that's for casual purposes 'mostly pure'.

Otherwise I can't even say I'm 'British', because who knows what mix I am if I go back further than I have record of, which is just silly, we know what we mean.

[danparsonson]

You're very close to following that line of enquiry to its logical conclusion, which is that our nationalities tell us little of any real value except what our home culture was like where and when we grew up. Personally I've come to regard identifying as any nationality as silly except for legal purposes.

We're humans, and humans have always and always mixed between cultural groups, except in rare instances of total isolation; such people are not 'pure' anything, but they would likely be inbred. There is no 'pure' genetic strain of any race or indeed any organism. Whatever divisions there are between us are extremely blurry and constantly changing.