Marvin Isley: Bass guitarist who co-wrote many of the Isley Brothers' biggest hits

Over the years, many black American soul groups have been formed around family members, notably the Jackson Five, Sister Sledge and the Staple Singers.

At their peak, the Isley Brothers boasted six family members including the bassist and youngest brother, Marvin. He co-wrote many of their hit songs including "Harvest For The World", "Highways Of My Life" and "It's A Disco Night", and he also co-wrote "Caravan Of Love", a No 1 for the Housemartins in 1986.

The Isley Brothers were encouraged by their parents, O'Kelly and Sally. At first, their children sang in their church choir in Cincinnati, Ohio, but a gospel quartet was formed in 1955 with Kelly (born 1937), Rudolph (1939), Ronald (1941) and Vernon (1942) with their mother as accompanist. They had some regional success but Vernon died in a traffic accident in 1957. Their parents encouraged them to continue as a trio and the brothers recorded for a few small labels in New York. Marvin Isley was born in Cincinnati in 1953 and the whole family were to move to Teaneck, New Jersey after the death of the father in 1958 and the brothers' subsequent success.

In 1959 the Isley Brothers scored with the raucous, two-part single, "Shout", and they followed it with the equally frenzied "Twist And Shout" (1962), both songs becoming British beat group standards. In 1964 the three brothers formed T-Neck Records but the label was short-lived as the brothers were signed to Tamla-Motown and had international success with "This Old Heart Of Mine".

O'Kelly Isley had told the three brothers to learn instruments, but they were content to be vocalists. However, band members often left instruments in the house and both Ernie (born 1952) and Marvin showed an interest. From 1969, it seemed inevitable that they would join the band full-time once their studies were complete.

In 1969, the brothers followed the funky rhythms of James Brown and Sly and the Family Stone for "It's Your Thing", a US No 2, and then covered Stephen Stills' "Love The One You're With". After Marvin graduated, the band expanded to a six-piece, recording for the revitalised T-Neck label. Ronald was a versatile lead vocalist with Kelly and Rudolph in support, Ernie played guitar, Marvin bass and Chris Jasper, Rudolph's brother-in-law, keyboards. The group dressed in the fashions of the time but the older brothers looked preposterous in fringe jackets and jump suits.

The new-look Isley Brothers revitalised "That Lady", which they had first recorded in 1964. The new version had an insidious, funky feel, largely due to Ernie, who was inspired by Jim Hendrix. At times, Ernie overplayed the effects (such as the wah-wah pedal) but he was a very competent guitarist. "That Lady" was a million-seller and it was followed by a soulful version of Seals and Crofts' easy listening rock song, "Summer Breeze", which has become one of the great summer anthems.

In 1976, the Isley Brothers wrote a poignant song about world poverty, "Harvest For The World", which was recorded as a single and the title track of an album. Its insidious dance rhythm and fine melody combined to make this a perfect song, and it was also a UK hit for the Christians in 1988. Marvin was an industrious musician, always willing to learn, but he refused to accept his diabetes, ignoring medical advice and doing what he wanted.

The Isley Brothers often recorded political songs about black pride, notably on the albums, The Heat Is On (1975) and Go For Your Guns (1977). They had US hits with "Fight The Power", "The Pride" and "Take Me To The Next Phase". They enjoyed emulating the sexual come-ons of Marvin Gaye and the highly sensuous "Between The Sheets" was a huge R&B hit in 1983.

Their album title, 3+3, said it all. The new members were treated like junior partners and they didn't think the split in the proceeds was fair. Things came to a head in 1984 when Ernie, Chris and Marvin branched out as Isley, Jasper, Isley. This brought out their own vocal ability and they released some strong, rock-based albums, Broadway's Closer To Sunset Boulevard, Caravan Of Love and Different Drummer. A plea for universal love, "Caravan Of Love" was a No 1 R&B single in the States.

Back as the original threesome, the Isley Brothers continued to record but Kelly died in 1986 and Rudolph became a minister in 1989. The four remaining musicians resolved their differences in 1989 and became "The Isley Brothers featuring Ronald Isley". Marvin dated and married a flight attendant and started a family.

The new-look Isley Brothers did well but Marvin's health was deteriorating. He had a stroke in 1995 which left him without the use of his left hand. He had to leave the band, and two years later both his legs were amputated.

The financial problems in the Isley Brothers continued and the division of assets after Kelly's death was settled out of court; Ronald went to jail for tax evasion. The Isley Brothers were inducted into the Rock And Roll Hall Of Fame in 1992 and their work has often been sampled, an example being Public Enemy's "Fight The Power" (1989).

Marvin Isley, bass guitarist and songwriter: born Cincinnati 18 August 1953: married (one son, two daughters): died Chicago 5 June 2010.