The New England Historic Genealogical Society said Obama's mother, Stanley Ann Dunham, and Brown's mother, Judith Ann Rugg, descend from Richard Singletary of Haverhill, Mass. He died in 1687 at the age of 102.
"I think it's a really interesting thing, where you have the separation between a Democrat and a Republican, but you have one link," said David Allen Lambert, the society genealogist who discovered the connection with colleague Chris Child.
Lambert said the work was aided by prior research about Obama, as well as Brown's cooperation with the society.
"I'm glad to be in such distinguished company," Brown said of the findings.
The genealogical chart shows that Obama descends from Richard's eldest son, Jonathan Singletary. He later changed his surname to Dunham. Brown, meanwhile, descends from Jonathan's brother, Nathaniel Singletary. - AP