Little is known about the exact origin of the music now known as the blues. No specific year can be cited as the origin of the blues, largely because the style evolved over a long period and existed in approaching its modern form before the term blues was introduced and before the style was thoroughly documented. Ethnomusicologist Gerhard Kubik traces the roots of many of the elements that were to develop into the blues back to the African continent, the "cradle of the blues". One important early mention of something closely resembling the blues comes from 1901, when an archaeologist in Mississippi described the songs of black workers which had lyrical themes and technical elements in common with the blues. African roots There are few characteristics common to all blues, as the genre takes its shape from the distinctive attributes of each individual performance. Some characteristics, however, were present prior to the creation of the modern blues, and are common to most styles of African American music. The earliest blues-like music was a "functional expression, rendered in a call-and-response style without accompaniment or harmony and unbounded by the formality of any particular musical structure". This pre-blues music was adapted from the field shouts and hollers performed during slave times, expanded into "simple solo songs laden with emotional content". Many of these blues elements, such as the call-and-response format, can be traced back to the music of Africa. The use of melisma and a wavy, nasal intonation also suggests a connection between the music of West and Central Africa and the blues. The belief that blues is historically derived from the West African music including from Mali is reflected in Martin Scorsese’s often quoted characterization of Ali Farka Touré’s tradition as constituting "the DNA of the blues". Perhaps the most compelling African instrument that is a predecessor to an African-American instrument is the "Akonting", a folk lute of the Jola tribe of Senegambia. It is a clear predecessor to the American banjo in its playing style, the construction of the instrument itself and in its social role as a folk instrument. The Kora is played by a professional caste of praise singers for the rich and aristocracy (called griots or jalis) and is not considered folk music. Jola music may not have been influenced much by North African/Middle Eastern music, which may point to African American music not being, according to