When Henry Louis Gates Jr., host of the new PBS television series African American Lives, calls slavery the ghost in the attic of America’s history, Mae Jemison politely disagrees. “I think you’re being too generous,” says Jemison, ’77, a physician, medical researcher, university professor, philanthropist and former astronaut. “Slavery is more like the rotten fruit in the refrigerator that smells, and no one can figure out where it’s coming from.”

Jemison is one of eight prominent African-Americans featured in the four-hour series premiering in February. Co-produced by Thirteen/WNET New York and Kunhardt Productions, the series aims to repair one effect of slavery: its severing of African-Americans’ family roots.

Aided by historians, genealogical experts and research tools including DNA analysis, the project fills in long-missing branches of family trees for the eight subjects, among them Whoopi Goldberg, Quincy Jones, Chris Tucker and Oprah Winfrey. Harvard professor Gates makes use of oral histories, photographs, film clips, music and old documents—and ultimately reunites one of the participants with his ancestral community in Africa.

For Jemison, there is the revelation of a ledger showing the sale of her great-great-grandfather, Adam, at age 8. He was valued at $400.