Rock and Roll invented by black folks, adapted by white folks. This whole, "it has European" influences is a bunch of revisionist bullshit..
White people had their music, black people had theirs, and the black folks was better so the white folks started to become influenced by it. Personally I just don't hear any European influence in late 19th century and early 20-th century black music, period.
The very scales and polyrhythms which typified "black" music was vilified in European musics.. That European music also had "call and repeat" doesn't inherently mean that black music was influenced by it, indeed, the style of white American "call and repeat" was very different from the Africanized versions in black music.
If we're talking about AFTER the 1950s then there is a lot more borrowing, but if we're talking about music in its proto-developing stage, the physical divide of segregation did indeed dissuade cross-cultural mixing of the music.
It is a matter of historical fact that black folks pioneered rag time, then blues, then jazz, then rock and roll, then soul music.
Today Rap music is the Lakers