He is right though, the average Japanese is 15% jomon bvll
It's just that in some it shows and in others it doesn't

Well, this was quite the thing to learn about and look up. Really catches one off guard to realize that even the most homogeneous populations still have some degree of ethnic distinctions. For those more curious, what I researched up from wiki seems to be that jomon are the indigenous while the yayoi are theorized to be from korea or china.
I don't know if these pictures can be treated accurately, but it looks like the "asian" appearance came more from the yayoi

If you'd isolate that jomon face and told me to guess, I might've taken a stab at european or middle east before asian.
I don't know how to feel about that, given that I'm asian…