Blam, may I know if you have any theories regarding how a caucasian-looking people (the JOMON, and the AINU) come to be living in Japan, which is so far away from Europe ???
It's incorrect to classify the Jomon/Ainu as Caucasians.
There are two events in the last 100,000 years that define humans today. The Toba (near-extinction event) volcano explosion (74,000 years ago) reduced the worldwide human population to 2-10,000 people worldwide and produced many new 'branches' on the human tree (this bottleneck is still in our DNA)...the Jomon/Ainu types were probably defined at this event and they dominated large areas of Asia for thousands of years.
The second event, The Last Glacial Maximum(LGM), the coldest period during the Ice Age, occurred 23-18,000 years ago with another new 'branching' of human types. It was this event (I believe) that defined both the Caucasians and Mongoloids probably from a common source and its root was probably the Jomon/Ainu. The oldest (undisputed) Mongoloid skeleton ever found is 10,000 years old. The northern Asians, with the extreme Mongoloid features such as flat face, peculiar eyelid, Sindont teeth and lighter skin were a branch from the southern Mongoloids, Sundont teeth, etc.
I've come to believe that the 'homeland' of today's Caucasians is somewhere around present day Gansu Province, China.
Try to visualize the world during the most extreme time during the Ice Age (23-18,000 years ago), Europe is isolated and frozen while SE Asia (including Sundaland) was nice and balmy for thousands of years and humans must have flourished there. It was during the LGM that groups of people in the northern regions were isolated and I think this isolation produced the Caucasian and Mongoloid people of today. Caucasians just happened to be the ones who migrated to Europe as the Ice Age ended replacing the Neanderthals.