200,000 years ago, a new species, Homo sapiens, appeared on the African landscape. While scientists have long imagined eastern Africa as a real-life Garden of Eden, the latest research suggests humans evolved in many places across the continent at the same time. Now, the DNA of a 19th-century African-American slave reveals that during the early days of our species, our ancestors continued meeting, mating and hybridizing with other human types in Africa — creating ever greater diversity within us.