[Yosemitest]

... while researching his Caucasian mother, Stanley Ann Dunham’s lineage, Ancestry.com genealogists found her to have African heritage as well,
which piqued the researchers’ interest and inspired further digging into Obama’s African-American roots.
In tracing the family back from Obama’s mother, Ancestry.com used DNA analysis to learn
that her ancestors, known as white landowners in Colonial Virginia, actually descended from an African man.Existing records suggest that this man, John Punch, had children with a white woman
who then passed her free status on to their offspring. ...


(source)

[donmeaker]

Southern ‘peculiar institution’ was not as race based as commonly thought. The slaves at Arlington and other old plantations became increasingly white as time went on. Slave catchers were often paid a premium for whites that they could kidnap and in the slave states, paperwork could be “improved” to assure that the kidnapped poor whites would be retained as slaves to the mutual profit of the white plantation owner, the judge and the slave catcher. Often the judge was also a plantation owner.