In my (rational) mind, the Occam's razor point of view clearly signals that the people at Paracas, Peru, believed that an oblong skull was cool. So they bound their children's heads to deform them into shapes that they found cute. They were normal human beings like you or me.
Now, to imagine that they were aliens and that they had alien DNA in them is, to put it mildly, really crazy.
In the first place: why would aliens have DNA at all? The means for replicating protein could be based on some other set of molecules. The Universe is vast, I don't expect Star Trek-like aliens with humanoid appearance to be found when we finally encounter intelligent extraterrestrial beings.
They could have their biochemistry based on any kind of molecule! How about silicone?
The panspermia theory proposed by Swedish chemist Svante Arrhenius is very interesting and even probable (Panspermia: hypothesis that life exists throughout the Universe and is distributed by meteorites and comets as they collide with newly formed planets), but it is very different from the idea of extraterrestrials copulating with humans.
I found the paper about their HLA. And will post on it soon.
Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2014 by Austin Whittall ©