After watching Ken Burns' Jazz and reading several articles after that, especially one by Stanley Crouch, all of which asserted strongly the exclusive African-American provenance of jazz, I decided to apply some Sherlock Holmesian deductive reasoning to the subject:
To clarify the matter of jazz as a fundamentally African-American art, you must eliminate everything in and about the music that was not created by African-Americans. First, get rid of all those white-invented instruments: piano and all keyboards; trumpet, trombone and all other brasses; clarinet, saxophones and all woodwinds, all strings (except banjo). Take away all white-devised organizations consisting of same, such as orchestras and bands. Then delete all white-created musical practices such as staff notation, even-tempered scales and diatonic harmony. Shred those caucasoidal music structures like symphonies, sonatas, waltzes, marches, 32-bar popular songs, etc. After making all these excisions, what remains? A bunch of guys beating drums in exquisite polyrhythms. Sounds a lot like Africa to me. But not the U.S.A.!