On US slavery’s 400th anniversary, how ancestry quests help heal

lipping through his social studies textbook as a seventh grader in the 1970s, John F. Baker Jr. was stopped cold by an old black-and-white photo of four African Americans dressed in 1890s finery in front of a plantation home. The unidentified woman in the photo staring seriously out at him reminded him of his grandmother – and a tickle of curiosity was triggered every time he opened the book.

Coincidentally, when that grandmother came to see Mr. Baker’s family near Nashville for her annual visit in 1976, she asked the...