Wynton at Harvard, Chapter 10: From the African 6/8 Rhythm to the American Shuffle 

Shuffle and Swing are derived from laying that African 6/8 pattern on top of the two-beat pulse of marches and concert band music. In terms of drumming, early Swing drumming was quite plainly an adaptation of the rudiments and rhythms used in concert marches (John Philip Sousa, etc.), played with a “triplet” feel derived from that 6/8 time rhythm, and syncopations coming from Ragtime vocabulary developed by pianists “jazzing up” classical and popular tunes. The concert brass band is of course a Western European immigrant to the U.S., following stylistic traditions of the symphony orchestra but without strings; as is the folk music of Appalachia music (descended largely from Irish and English folk music). The ride cymbal rhythms we recognize as Shuffle and Swing patterns are descended from the overlay of the two-beat pulse and the (already syncopated) 6/8 rhythm. While the two pulse is present in the 6/8, this overlay intentionally makes the two beats much more prevalent (as in a march) and the 6/8 feels like triplet based subdivisions of that two beat pulse (with more emphasis on them and their syncopations than in marches). This particular evolution of the African rhythm occurred in America, starting in New Orleans but quickly spreading up the Mississippi River to places such as Kansas City and Chicago and then outward to the coasts, and developing further all over. As this influence found the ears of Appalachian musicians, it affected the rhythmic sensibilities of Western Swing and Bluegrass, which evolved in their own directions and in turn reciprocated with their influence on Jazz and Blues (and on Rock and Roll later). This African rhythm (and others) met different influences in South and Central America and the Caribbean, and evolved in different ways in those places, creating a whole bunch of unique song styles that we typically lump under the misleading heading, “Latin.” Again, those styles reciprocated by influencing American Jazz and Popular music later on. Influences continue to bounce back and forth, though these days it can happen so fast that there may not be time for things to coalesce into distinct regional styles before spreading around the world; Earth Music gets more homogeneous as technology makes the planet smaller.