Where did the Japanese people come from?

Although there are people who believe in the racial purity of the Japanese, current studies hold that the physical features of the Japanese people reveal their derivation from a mixture of several ethnic groups.
So, what racial groups comprise this mixture?
We can say that the Japanese stock was created over a long period of time by the gradual mixture of the Jomon strain, an ethnic group from South-east Asia that crossed the sea to Japan the Yayoi strain.
Tungusic people arriving through the Korean peninsula, and the Ainu ethnic group.