In the Senate race between Elizabeth Warren and incumbent Scott Brown, discussions about race have played a central role. But arguments and questions surrounding Warren’s proclaimed Native American ancestry are just the newest chapter in a long history of battles over racial heritage in the American political arena. In the 19th and early 20th centuries, the Irish and Italian populations in Boston used politics to debate each other’s whiteness.

Today, changing definitions of race and the rapid evolution of science have altered many ideas about ethnic heritage and complicated arguments about race in politics. Reporter Phillip Martin examines the nuances of modern Native American identity and puts his own DNA under the microscope.