A TEAM of genealogists has found evidence that US president Barack Obama could have descended from an African slave through his white mother.
The most likely lineage route, Obama's black father, had been had followed and exhausted by researchers.
Instead, the link is through an examination of his white mother's family history, according to two years' research by genealogists with Ancestry.com.
"We were surprised and excited to make that connection," said Joseph Shumway, a member of the Utah-based Ancestry.com team.
Obama's father was from Kenya and his mother from Kansas.
It had been generally assumed that the president had no slave ancestors because researchers could not find it through the lineage of his father.
But no one had yet performed any exhaustive research into the lineage of his white mother, who turns out to have a mixed-raced family history.
Ancestry.com now says the maternal line traces back to one of the first documented African slaves in the US.
The company said Obama could be the 11th great-grandson of John Punch, an African slave in colonial Virginia.
He is believed to have had children with a white woman, starting a family line that led generations later to Mr Obama's mother.
The White House declined to comment.