>>20734768Yayoi make up over 70%, so they are the genetic substrate.
On a related note, I recently rewatched Princess Mononoke and noticed that the elders in the beginning had large beards, I realized that Ashitaka and Mononoke were both meant to be racial Emishi, a late surviving population with very high Jomon admixture.
https://en.wikipedia.org/wiki/Emishi 