In historic times the Jomon became the Emishi, and they in turn the Samurai class.
The Ainu are not native to Japan, as the civil wars progressed in the Southern Islands and the climate deteriorated the Jomon, et al, left Hokaido and other islands in the North and Ainu from the continent moved in.
Actually, the white people in Southern and Central latitudes of Europe are part of a branch that split off from the original white people ~ who now live primarily in the Arctic and Subarctic. Again, that happened about 15,000 years ago although an earlier branch appears in America 20,000 years ago.
East Asians and Europeans carry genes that suppress formation of melanin ~ both methods are different! The European Neanderthals had a third set of genes that suppressed formation of melanin. It is important in the Northern reaches of the Northern hemisphere to have light skin.