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Barack Obama has lived one version of the American Dream that has taken him to the steps of the White House. But a few miles from where the Democratic presidential candidate studied at Harvard, his Kenyan aunt and uncle, immigrants living in modest circumstances in Boston, have a contrasting American story.

Zeituni Onyango, the aunt so affectionately described in Mr Obama’s best-selling memoir Dreams from My Father, lives in a disabled-access flat on a rundown public housing estate in South Boston.

A second relative believed to be the long-lost “Uncle Omar” described in the book was beaten by armed robbers with a “sawed-off rifle” while working in a corner shop in the Dorchester area of the city. He was later evicted from his one-bedroom flat for failing to pay $2,324.20 (£1,488) arrears, according to the Boston Housing Court.

The US press has repeatedly rehearsed Mr Obama’s extraordinary odyssey, but the other side of the family’s American experience has only been revealed in parts. Just across town from where Mr Obama made history as the first black president of the Harvard Law Review, some of his closest blood relatives have confronted the harshness of immigrant life in America.

In his book Mr Obama writes that “Uncle Omar” had gone missing after moving to Boston in the 1960s – a quarter-century before Mr Obama first visited his family in Kenya. Aunt Zeituni is now also living in Boston, and recently made a $260 campaign contribution to her nephew's presidential bid from a work address in the city.

Speaking outside her home in Flaherty Way, South Boston, on Tuesday, Ms Onyango, 56, confirmed she was the “Auntie Zeituni” in Mr Obama’s memoir. She declined to answer most other questions about her relationship with the presidential contender until after the November 4 election. “I can’t talk about it, I just pray for him, that’s all,” she said, adding: “After the 4th, I can talk to anyone.”

A photograph of Ms Onyango was later shown to George Hussein Onyango, Barack Obama’s half-brother in Nairobi, who confirmed that it was their aunt. George Onyango, 26, the youngest child of Barack Obama Sr, said that he had spent weekends with his Aunt Zeituni when he was growing up, and instantly recognised her.

George Onyango said that his aunt had left for the US about eight years ago but sent him e-mails. “She left to find work and I suppose she thought her life would be better there,” he said. “She was kind and caring.”

In his memoir Mr Obama describes the joy of meeting his father’s family during his first visit to Kenya in 1988. Aunt Zeituni, then a computer programmer at Kenya Breweries in Nairobi, is portrayed as a feisty woman who proclaims herself “the champion dancer”. Uncle Omar, by contrast, remains a mysterious figure who left for America and never came back. At one point in the book a half-sister tells Mr Obama that people “like our Uncle Omar, in Boston” move to the West.

“They promise to return after completing school. They say they’ll send for the family once they get settled. At first they write once a week. Then it’s just a month. Then they stop writing completely. No one sees them again.”

Aunt Zeituni and Uncle Omar are the children of Mr Obama’s grandfather Hussein Onyango Obama, by his third wife – the woman Mr Obama calls “Granny” because she raised his father. Mr Obama’s father, Barack Sr, was Onyango Obama’s son by his second wife, Akumu. That makes Zeituni and Omar a half-sister and half-brother of Mr Obama’s father, or Mr Obama’s half-aunt and half-uncle.

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