Blues

Originated in African-American communities of primarily the "Deep South" of the United States around the end of the 19th century from spirituals, work songs, field hollers, shouts and chants, and rhymed simple narrative ballads. The blues form, ubiquitous in jazz, rhythm and blues, and rock and roll is characterized by specific chord progressions, of which the twelve-bar blues chord progression is the most common.

Associated Sub-Genres: Acid Blues, African Blues, Blues-Rock, Blues Shouter, Boogie-Woogie, British Blues, Canadian Blues, Chicago Blues, Classic Female Blues, Contemporary R&B, Country Blues, Delta Blues, Detroit Blues, Electric Blues, Gospel Blues, Hill Country Blues, Hokum Blues, Jazz Blues, Jump Blues, Kansas City Blues, Louisiana Blues, Memphis Blues, Piano Blues, Piedmont Blues, Punk Blues, Rhythm And Blues, Soul Blues, St. Louis Blues, Swamp Blues, Texas Blues, West Coast Blues

Source: http://en.wikipedia.org/wiki/Blues