Around 200,000 years ago, a new species, Homo sapiens, appeared on the African landscape. While scientists have 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. DNA from a 19th-century African-American slave is forcing geneticists to re-think the origins of our species. The theory is that our ancestors met, mated and hybridized with other human types in Africa — creating ever greater diversity within our species.

• Kerry Shale