ben affleck has revealed name of the slave-owning ancestor which he got pbs to cut from finding my roots .
he says his freedom rider mother chris anne was descended from benjamin cole , a georgia slave-owner ` about six generations ' ago .
oscar winner apologized last night for having pbs show cut revelation of his slave-owning roots , which was first revealed last week by daily mail online .
` i did n't want any television show about my family to include a guy who owned slaves . i was embarrassed , ' he wrote on facebook .
pbs has launched an internal investigation into whether or not finding your roots violated their editorial standards and its host 's future is in doubt .