Reggae's origins are in traditional African and Caribbean music; American rhythm and blues; and in Jamaican ska and rocksteady.
The word reggae may have been first used by the vocal group the Maytals, in the title of their 1968 rocksteady hit Do the Reggay. The Oxford English Dictionary says the origin of the word is unknown, but may be derived from the Jamaican-English word rege-rege, meaning quarrel. Other theories are that the word means torn clothes or that the term came from the word streggae (a Jamaican slang term for prostitute).
By the mid 1970s, reggae was getting radio play in the United Kingdom on John Peel's radio show, and Peel continued to play much reggae during his career. Reggae has always had a fairly large following in the United Kingdom, especially during the 1970s and 1980s. In the second half of the 1970s, the UK punk rock scene was starting to take off, and some punk DJs played reggae records during their DJ sets. Certain punk bands, such as The Clash, The Slits and The Ruts incorporated reggae influences into their music. Reggae includes several subgenres, such as, roots reggae, dub, lovers rock and dancehall.
The toasting style first used by 1960s Jamaican artists such as U-Roy and Dennis Alcapone influenced Jamaican DJ Kool Herc, who used the style to pioneer a new genre that became known as hip hop or rap. In Jamaica, the term Deejay or DJ is equivalent to the rapper or MC in American hip hop culture, while it is the selector who actually mans the turntables. Mixing techniques employed in dub music have influenced hip hop and drum and bass.
The dancehall genre developed around 1980, with exponents such as Yellowman, Super Cat and Shabba Ranks. The style is characterized by a deejay singing and rapping or toasting over raw and fast rhythms. Ragga (also known as raggamuffin), is a subgenre of dancehall, in which the instrumentation primarily consists of electronic music and sampling. Reggaeton is a form of dance music that first became popular with Latino youths in the early 1990s. It blends reggae and dancehall with Latin American genres such as bomba and plena, as well with hip hop. Reggae rock is a fusion genre that combines elements of reggae and rock music. The bands Sublime and 311 are known for this reggae rock fusion, as is singer Matisyahu, a Hasidic Jew, who blends it with traditional Jewish music. Billboard magazine named him "Top Reggae Artist" of 2006.
Reggae is always played in 4/4 time or swing time because the symmetrical rhythm pattern does not lend itself to other time signatures such as 3/4 time. Harmonically, the music is often very simple, and sometimes a whole song will have no more than one or two chords. The Bob Marley and the Wailers song "Exodus" is almost entirely comprised of A-minor chords. These simple repetitious chord structures add to reggae's sometimes hypnotic effect. However, Marley also wrote more complex chord structures, and the band Steel Pulse have often used very complex chord structures.
www.wikipedia.org/wiki/Reggae_music