@blablablahhjkl yes, there is a visible difference. In fact, it even made it to Keijo manga and anime. The point is, Asians have their coccyx bent inwards, and Caucasians and Africanoids - outwards, which, in turn, changes the shape of the butt because it's one of the important "anchors" for butt muscles to be attached to. As a result, Asian butts are much less emphasized dorsally than the butts of other races.
I was trying to find a good illustration since anatomy as a science is a science of visual representation, but I mostly get advertisements and erotica. Still, I'm trying to find a proper reference. And I hope I won't get banned for this.
Oh, and nota bene: You may very well find a mixed-race person with a European-looking butt and Asian face. That is almost inevitable within a diverse society. However, in a homogenous country like Japan, it's such an uncommon occurrence you can always see clamor around any half-Japanese or foreigners in anime, filled with both awe and fear.