It's called scientific racsim.
Welcome to the club of the educated!! :)
Here's the thing. The oppressors need to somehow prove that Natives didn't originate in America. They have to rid themselves of their guilt. They feel that if Natives were immigrants then they have equal rights to the land as oppressors.
It is Theory! It is not fact at all! For more information read the book "Red Earth White Lies". It is based in actual science, not just one frame but looks at many theories.
I am a Native woman. I am sooooooo tired of people believing this information on blind faith. People need to get educated and do their research. They need to stop supporting oppression and start supporting cultural respect.
EDIT: I just read the national geographic article. It is only suggested. This means it's not proven (even if it was I wouldn't believe it, i'd have to look into the science first).
People need to understand that all these new DNA studies that are being done are So Very New. We have had so much science in the past that seemed correct but later turned out horribly incorrect (i.e. we thought the world was flat). We need more time to pass before anyone can really understand DNA. Also this guy who is doing this project seems to be getting a LOT of money from it. And we know that money drives science (not the other way around). This creates a lot of room for bias.