If you think about it, Africans are the real "pure blooded" people, because they didn't interbreed with the Neanderthals like Europeans did after migrating out of Africa.
Neanderthals originally came from Africa too, they didn't spontaneously generate in Europe. There's no pure blooded people, we are products of the places our ancestors lived based upon evolutionary and social pressures.
I'm sorry? I don't understand why you'd think I think that? This was like hundreds of thousands of years ago, so whatever their skin colour there would have been plenty of time for melanin levels to change since then