and roll". Not often acknowledged in the history of rock and roll, Todd Storz, the owner of radio station KOWH in Omaha, Nebraska, was the first to adopt the Top 40 format (in 1953), playing only the most popular records in rotation. His station, and the numerous others which adopted the concept, helped to promote the genre: by the mid 50s, the playlist included artists such as "Presley, Lewis, Haley, Berry and Domino". Early rock and roll Origins The origins of rock and roll have been fiercely debated by commentators and historians of music. There is general agreement that it arose in the Southern United States – a region that would produce most of the major early rock and roll acts – through the meeting of various influences that embodied a merging of the African musical tradition with European instrumentation. The migration of many former slaves and their descendants to major urban centers such as St. Louis, Memphis, New York City, Detroit, Chicago, Cleveland, and Buffalo meant that black and white residents were living in close proximity in larger numbers than ever before, and as a result heard each other's music and even began to emulate each other's fashions. Radio stations that made white and black forms of music available to both groups, the development and spread of the gramophone record, and African-American musical styles such as jazz and swing which were taken up by white musicians, aided this process of "cultural collision". The immediate roots of rock and roll lay in the rhythm and blues, then called "race music", in combination with either boogie-woogie and shouting gospel or with country music of the 1940s and 1950s. Particularly significant influences were jazz, blues, gospel, country, and folk. Commentators differ in their views of which of these forms were most important and the degree to which the new music was a re-branding of African-American rhythm and blues for a white market, or a new hybrid of black and white forms. In the 1930s, jazz, and particularly swing, both in urban-based dance bands and blues-influenced country swing (Jimmie Rodgers, Moon Mullican and other similar singers), were among the first music to present African-American sounds for a predominantly white audience. One particularly noteworthy example of a jazz song with recognizably rock and roll elements is Big Joe Turner with pianist Pete Johnson's 1939 single "Roll 'Em Pete", which is regarded as an important