"I'm beginning to think that both the Caucasians and Mongoloids split from the Jomon - Ainu types who appear to have dominated large areas of Asia 10k+ years ago."
Completely valid. I agree it's possible, almost probable.
"Also, maybe these people were moving in the opposite direction than believed by most..."
Interesting. Maybe originated from the Chinese highlands? Though the quest begs then... what wiped them out of thaty region for several generations?
What region and what time? I'll work on it if I don't already know. Thanks.