How about hair and skin samples from live indians?
The DNA results of the mummies mentioned in the book Wurde Amerika in der Antike entdeckt? by Hans Giffhorn indicate Siberian [native American] on the female ancestors’ side and Western European on the male ancestors’ side. My view is that in antiquity a ship of European men landed on the south American coast, then sailed up the Amazon river. The men then climbed the foothils of the Andes, either in an effort to cross the continent or in an effort to escape heat of the tropical lowlands. There they stayed and produced offspring with the local women and thus founded a light-skinned-light-colored-hair tribe.