Dolphus T Shields (left), Mrs Obama's ancestor, has a white father who links the First Lady (pictured far right as a baby) with slave-owning the decedents of slave owners who still live in the South. New York Times journalist Rachel L Swarns used DNA testing and historical documents to track down Mrs Obama's living white family members for her new book, 'American Tapestry: The Story of the Black, White and Multiracial Ancestors of Michelle Obama.' http://www.dailymail.co.uk/ushome/index.html
I’ve read accounts that Jefferson, Jackson, Lincoln, Harding, Eisenhower and possibly other presidents had black ancestors.