In her book, "American Tapestry: The Story of the Black, White and Multiracial Ancestors of Michelle Obama," Swarns traced Obama's DNA back to Georgia slave owners and linked her to Joan Tribble, 69, whose ancestors are interred in Rex, Ga.
The New York Times reported Obama was aware of her white slave-owner roots but knew little about them. Swarns found Obama has white relatives in Georgia, South Carolina, Alabama, Texas and elsewhere, running the gamut from blue-collar workers to professionals who never knew they were related to the first lady.
"I can't really change anything," Tribble told the Times, saying she would like to meet the first lady. "But I can be open-minded to people and accept them and hope they'll accept me."
Obama and Tribble can trace their family ties to Henry Wells Shields, who had a 200-acre farm on which he grew cotton, corn and sweet potatoes. The Times said Shields owned Melvinia Shields, Obama's maternal great-great-great-grandmother. The Times said Shields' son Charles likely fathered Dolphus T. Shields, Obama's maternal great-great-grandfather, when Charles was about 20 and Melvinia, 15.
Swarns' research indicated Melvinia, who died in 1938, was a field slave and after the Civil War bore more biracial children.
Obama has not commented on the findings.